Conflicting Baselines: a climate nerd winge

I find it incredibly frustrating and baffling that the IPCC and other major climate science bodies like NASA use a variety of unreconciled baselines for global temperature changes in the reports. Sometimes it is 1951-80, sometimes it is 1981-2010, sometimes 20thC average and so on.* I have not found a convenient set of translations between these baselines in the reports that would enable you to, say, add 0.4ºC to get from a 1880-1909 baseline to a 1951-80 baseline.
*Since climate averages are defined scientifically (at least by the recommendation of the WMO) as requiring a minimum of 30 years of continuous data, most baselines are 30 year periods, rather than single points in time.

Given that the UNFCCC negotiations are based on a preindustrial baseline ("hold the increase in global average temperature below 2°C above preindustrial levels", Cancun Agreement, 2010), yet have never (to my knowledge) defined precisely what "preindustrial" actually means nor attempted to quantify its relation to other baselines, it is unconscionable that the IPCC have not made this a far more prominent frame for all their work. In other disciplines, preindustrial is generally taken to mean prior to 1750 or so. One challenge of using preindustrial as a baseline in negotiations for a legally-binding international agreement is that high quality temperature data from direct measurements (rather than proxies) with good global coverage only extends back into the 2nd half of the 19thC (depending on how good you want the coverage to be). Even if the IPCC noted that estimates of global temperatures prior to the late 19thC have error bars too large for meaningful negotiations and suggested that the UNFCCC make, say, 1880-1909 the universal baseline for negotiations, that would be defensible.

One reason they haven't done so is that this would probably require a reconfiguration of the global goals away from neat round numbers, since paleoclimate specialists (who reconstruct temperature data prior to the instrumental record from proxy data) say that between ~1750 and 1880-1909 there was likely about 0.2ºC of warming. Shifting to a goal of under +2ºC from 1880-1909 would probably (and should) be resisted by those nations most vulnerable to warming.

Why does this matter? (Beyond obsessive concerns for clarity from scientists and those of us who appreciate precision)

It matters because the vast majority of journalists fail to mention (and may well not even be aware of) the issue of different baselines. The media thus regularly refers to goals like keeping temperatures below +2ºC without specifying their assumptions. Since most new scientific publications use a baseline considerably later than preindustrial, this means that many articles reporting on scientific findings give a very misleadingly rosy picture of the scale of ambition required to achieve the agreed UNFCCC target. It is much easier to meet a +2ºC from 1981-2010 target than a +2ºC from preindustrial (=~1750, or even 1880-1909) target.

And this matters because I expect that the number of parliamentarians who grasp these distinctions is also quite limited.

Global warming over the last 16 years

A brief response to a common claim.

Don't breathe too deeply, and other stories

Air pollution: 97% of EU citizens are exposed to levels of tropospheric ozone above WHO recommended limits. "On average, air pollution is cutting human lives [in Europe] by roughly eight months and by about two years in the worst affected regions". The situation is considerably worse in many parts of the world. The true cost of the public health burden on respiratory function of burning coal in China, for instance, is perhaps as high as 7% of annual GDP, even before climate costs are considered. A 2011 study of the external costs of coal in the US (excluding climate costs) found an annual price tag between 1/3 and 1/2 a trillion dollars.

Climate change is here: Climate change is already contributing to the deaths of nearly 400,000 people a year and costing the world more than $1.2 trillion, wiping 1.6% annually from global GDP, according to a new study. The impacts are being felt most keenly in developing countries, according to the research, where damage to agricultural production from extreme weather linked to climate change is contributing to deaths from malnutrition, poverty and their associated diseases. Air pollution caused by the use of fossil fuels is also separately contributing to the deaths of at least 4.5m people a year, the report found. That means failing to tackle a fossil fuel based economy will contribute to something like 100 million deaths by the end of next decade.

Warming oceans: warming and acidification will cut the productivity of fisheries in many countries. "About 1 billion people depend on seafood as their main source of protein. But some of those countries most dependent on fishing are expected to lose up to 40% of their fish catch by the middle of the century." Hardest hit will be the Persian Gulf, Libya, and Pakistan. Of course, this is just from carbon-related changes and does not take into account patterns of overfishing, invasive species, pollution, eutrophification, stratification, shifting currents or habitat loss from coral reef degradation. And even the size of fish will shrink in warmer oceans.

Dying trees: Who will speak for the trees? Trees are dying by the millions all around the world due to a wide range of factors. Not just deforestation - which, though it has slowed down a little in Brazil, still continues with increasing rapidity elsewhere - but also due to ground level ozone pollution, infectious diseases (a third of all UK trees face wipeout from a new fungal threat that is expected to wipe out over 90% of Danish Ash trees) and a variety of threats associated with climate change, such as heat stress, invasive species (pine bark beetle) and droughts. For instance, last year's drought in Texas killed over three hundred million trees (or about 6% of all its trees). Heat stress has been linked to widespread tree mortality in scores of studies over the last few years.

Ocean acidification: A basic primer with FAQs, including excellent brief answer to common misconceptions.

Killer cats: How much do cats actually kill? The Oatmeal summarises some recent research. There are hundreds of millions of domestic cats around the world, and tens or hundreds of millions of feral cats. They are taking a big toll on small wildlife.

Australian coal: Australia's carbon price, far from signalling the "death of the coal industry" as claimed repeatedly by the Opposition, has apparently done little to dent the explosive growth of coal exploration in the country. Australia is the world's largest exporter of coal, fifth largest extractor of fossil hydrocarbons globally and has the highest per capita domestic carbon emissions in the OECD. Despite setting very modest carbon reduction targets in recent legislation, both government and industry are planning on a doubling of coal exports in the coming decade, representing emissions many times greater than Australia's tiny domestic reductions, which will largely come from international offsets in any case.

The Arctic is melting: 18 reasons to care

Arctic sea ice has once again smashed all kinds of records - for extent, area and volume. Every year a huge amount of ice melts in summer and refreezes in winter, but the trend over the last few decades has been strongly downwards, especially during the summer months. In fact, this year, the extent of ocean with at least 15% sea ice cover declined to a level less than half of what it used to average just twenty years or so ago. Through it is harder to measure, the volume of summer sea ice is down by about three quarters from what it used to be. I posted an introduction to sea ice area, extent and volume back here.

When compared to our best reconstructions of the history of Arctic sea ice over the last 1450 years, the last few decades are, well, unusual. The graph above, which shows the ups and downs of summer sea ice extent over the years gives a sense of just how staggeringly quickly this part of the world is changing. Indeed, the collapse in sea ice is so rapid that it continues to stun even the scientists who have been watching it closely for decades. Back in 2007, the IPCC Fourth Assessment Report said that it was unlikely the Arctic would be seasonally free until after 2100.* Now, the UK Met Office says it is likely sometime between 2040 and 2060, most other Arctic organisations speak about sometime around 2030, while a handful of individual experts warn that, depending on weather conditions, it could be as early as the next Olympics in Rio. There is almost no evidence that this has occurred for at least the last few hundred thousand years (estimates range from 700,000 to 4 million years). *There are different definitions for what "ice-free" means. The most common is when extent drops below one million square kilometres, meaning that there might still be some ice clinging on around the north Greenland coast or in bays and inlets in the high Canadian Arctic, but effectively, the main ocean is free of ice.

Whatever the precise timing, why do we care? So what if some polar bears drown? Why does it matter to me what is happening thousands of miles away in the middle of an ocean amidst a deserted wilderness? Because the Arctic is closer than you think. The effects of declining summer sea ice are many. Here are eighteen reasons to care about the likelihood of a seasonally ice-free Arctic Ocean in the coming years. Only one is polar bears:

1. Polar bears: And walruses, seals and all the other unique Arctic wildlife that depend on sea ice. Seasonal sea ice loss threatens the unique and endemic Arctic biota. The polar bear is an photogenic icon, and as the largest terrestrial predator it instantly commands widespread respect and attention, but there is so much more at stake than simply polar bears.

2. Cultural loss. The loss of sea ice undermines the way of life of various indigenous groups in the Arctic, who rely on hunting and the ice for their livelihood and culture.

3. Infrastructure damage: As the Arctic region is warming, the permafrost that covers the land is both melting and being rapidly eroded. There are many structures and roads built on the permafrost that are already suffering severe damage.

4. Albedo change: Less floating white ice means more exposed dark water, which absorbs more solar radiation, increasing the total incoming heat flux of the planet, and specifically of the Arctic Ocean. The reflectivity of the planet's surface is called its albedo, and the decrease in albedo caused by loss of Arctic ice during the period when it is receiving 24 hours of sunlight is considered by many scientists to be the greatest single threat on this list.

5. Permafrost methane: A warming Arctic Ocean and atmosphere speeds the melt of permafrost in Canada, Siberia and Alaska, not only threatening infrastructure (see #3), but also releasing stored methane (CH₄), a highly potent greenhouse gas that degrades into carbon dioxide, making it both a short term climate nasty and a long term headache. The total amount of frozen methane is vast and although it unlikely to all melt quickly, it is soon likely to become a significant and sustained drag on efforts to cut emissions. More emissions from thawing permafrost means less room and time for us to make our own transition away from carbon-intensive energy systems.

6. Submarine methane: Warmer waters increase the rate at which vast submarine deposits of methane clathrates found along the Siberian continental shelf destabilise and are released to the atmosphere, giving a further kick to warming. Some observers are petrified this "clathrate gun" could end basically all life on earth in matter of years through a catastrophic self-perpetuating release. As I've noted previously, scientists are yet to see a convincing geophysical mechanism for this being a sudden and catastrophic release (with consequent spike in global CH₄) rather than a progressive leak resulting in an elevation of CH₄ with rising CO₂. This represents further drain on our carbon budgets, though the precise scale and timing of these emissions are less understood than those from terrestrial thawing.

7. More available heat: To convert ice at 0ºC to water at 0ºC takes energy, even though the temperature has not changed. The considerable energy involved in this phase change is called latent heat. Without ice in the ocean sucking up extra energy during summer, the solar energy that previous went into melting ice can go into the oceans (and later be released to the atmosphere). This is like removing a handbrake, though my back of the envelope attempts to quantify it suggest it will be significantly smaller effect than albedo change (#4). I'd like to see these calculations made by someone who knows what they are doing.

8. Wacky weather: This is something of a wild card and could prove to be the biggest danger to human society. Losing the ice is already changing wind patterns around the Arctic, which in turn affect the weather throughout the northern hemisphere. There is some evidence that more exposed water in the Arctic and a decreased temperature difference between the equator and pole (since the Arctic region is warming much faster than further south) is increasing the amplitude of the meanders in the jet stream. In turn, this slows down progression of the meanders, leading to "blocking patterns", where one region gets "stuck" in a certain weather pattern, whether heatwave, drought or flood. The 2010 Moscow heatwave that killed 11,000 people and sent the price of wheat skyrocketing (in turn helping to spark the Arab Spring), the 2010 Pakistan floods that displaced 20 million people, the 2010/11 record cold winters in Europe and parts of the US and the 2012 US heatwave and drought have all been linked to unusually persistent blocking patterns. Losing the ice may mean we see more of these kinds of things. The jury is still out on this theory, but if not precisely like this, the loss of Arctic sea ice will almost certainly affect wind circulation patterns and so weather both regionally and hemispherically.

9. Greenland melt: Over the long term, this may be the biggest change. The warmer the Arctic Ocean gets, the warmer Greenland is likely to get, and the faster its glaciers slide and melt into the sea. While floating sea ice doesn't affect sea levels (and there's relatively little of it anyway), there's enough ice on top of Greenland to raise sea levels by 7.2 metres (on average). As I read it, glacial draining and calving of the ice sheet is a larger sea level rise contributor than straight melting (thus the recent fracas over dramatic surface melt may not be the key issue for Greenland - remember, this recent melt event cut centimetres off a sheet that averages over two kilometres thick). The real danger is the acceleration of ice flow dynamics (i.e. the ice cube is more likely to slide off the table before it has finished melting). And the largest boost to glacier acceleration is from warming oceans meeting marine terminating glaciers. No one is entirely sure how long this will take, but it is a process that once it is underway in earnest, is likely to have a momentum of its own, meaning that our descendants will be committed to ever rising sea levels for centuries to come. The somewhat good news is that it is also a process that (on present understandings) is assumed to have some physical constraints due to friction (i.e. there are speed limits for glaciers, even in very warm conditions). The West Antarctic ice sheet, being largely grounded on bedrock well below sea level is actually more plausibly in danger of catastrophically sudden break-up, though warming in the Antarctic is currently only a fraction of what is being observed in the Arctic.

10. Resource conflict: An increasingly ice-free Arctic opens up a geopolitical minefield as nations scramble to take advantage of the resources previously locked away under the ice. The starter's gun for this race has well and truly fired, with various oil companies sending rigs to begin drilling for oil and gas this season. As one signal of the seriousness with which this is now taken, meetings of the Arctic council (comprised of nations bordering the Arctic) now attract Hillary Clinton rather than a minor government official.

11. More oil: The presence of significant amounts of oil and gas under the Arctic Ocean has been suspected and known for some time. Less ice means that fossil hydrocarbons that were previously off limits now become economically viable to extract, thus increasing the pool of available carbon reserves and so worsening the challenge of keeping most of them underground.

12. Fishing: Another resource now increasingly able to be exploited due to the loss of seasonal sea ice. Pristine (or somewhat pristine) marine ecosystems are thus exposed to greater exploitation (and noise pollution).

13. Shipping lanes: The fabled North West passage through the remote islands of Canada has been open to commercial shipping without icebreakers only four times in recorded history: 2011, 2010, 2008, 2007. The North East passage has also been open in recent years. These previously inaccessible Arctic shipping routes reduce fuel needs of global shipping by cutting distances (a negative feedback) but also brings more diesel fuel into the Arctic region, leaving black soot on glaciers (a positive feedback). I'm not sure which is the larger effect overall.

14. Toxin release: For various reasons, certain toxins and heavy metals from human pollution seem to accumulate in Arctic sea ice. As it melts, they are being released once more into the environment.

15. Invasive species: Melting ice reconnects marine ecosystems that were previously separated by ice, enabling migration of species into new regions, with unpredictable ecosystem changes as a result. This is already occurring.

16. Ocean circulation? These last three points are more speculative and I'm yet to see studies on them. But loss of sea ice could well change the patterns of ocean currents in the great global conveyor belt known as thermohaline circulation. This drives weather patterns throughout the entire globe.

17. Acidification acceleration? By increasing the open ocean surface area for atmosphere-ocean gas exchange, the rate of ocean acidification could slightly increase. Would this make any difference to ocean capacity to act as CO₂ sink or rate of acidification? This could well be irrelevant, but it is a question I have.

18 Political tipping point? The loss of virtually all perennial Arctic sea ice would be a highly visual and difficult to dispute sign of rapid and alarming climate change, representing a potential tipping point in public awareness and concern. If we are waiting for that, however, before we make any serious efforts to slash emissions (especially if it doesn't occur until 2030 or later), we'll already have so much warming committed that we'll pretty much be toast. At best, therefore, this point might consolidate public support for massive rapid emissions reductions already underway. These eighteen reasons can be summarised in five broad headings:

1. Direct effects upon local wildlife, human communities and infrastructure (1, 2, 3, 12, 14, 15);
2. Positive feedback affects that accelerate the warming process (4, 5, 6, 7, 11);
3. Changes to human economic and political systems through the opening up of previous inaccessible resources and routes (10, 13, 18);
4. Disruptions to the great atmospheric and oceanic circulation patterns that shape the experience of billions of people directly (8, 16);
5. Acceleration of long term threats (9, 17).

The loss of Arctic sea ice will not suddenly be the end of the world, but it represents a major milestone on the path to self-destruction along which we are currently hurtling with accelerating speed.

UPDATE: My opening graph needs some important further clarification. The unamended graph is a 40 year smoothed average, while the additional material displays year-on-year changes and so is not comparing apples to apples. However, using only 40 year averages to capture the dramatic changes of the last few years is also likely misleading. There is further discussion of this image here, here and here.

Ross Gelbspan summarises our climate predicament

This is a twenty-three minute talking head video that you can basically put on as an audio since there is practically nothing to see. But the grasp of our situation by this investigative journalist - who has spent fifteen years grappling with climate science, politics, journalism and ethics and published two major books on these matters - is superior to that of many other commentators I've come across. It is now a couple of years old, but still extremely relevant.

Does nature have a price? and other stories

Pricing nature: George Monbiot highlights the myopia of attempting to include "ecosystem services" within mainstream neoliberal economic thought. The initial government report noted that some of the services provided by natural ecosystems "may in fact be infinite in value". You don't say.

Ten Billion: A "play", reviewed here and here, in which noted Cambridge scientist Stephen Emmott plays noted Cambridge scientist Stephen Emmott. The only set is a recreation of his messy Cambridge office and the drama is Emmott delivering a lecture on our current predicament. describes himself as a "rational pessimist" and lays out the daunting, perhaps impossible, task before us in the coming decades where we face multiple converging crises. He concludes that the only rational way forward is radical cultural change with widespread embrace of lower consumption and fewer children (this is pretty close to what I think, with nuances regarding children), but thinks it is not going to happen (this is also basically what I think, though with all kinds of reasons why it is still worth trying). Given that those who will hear this are those willing to pay through the nose for a night of "theatre" more disturbingly horrifying than any fictional film, it's probably better to avoid reading too much into fact that all performances are sold out. Attempts such as this to piece together the various disparate pieces of information that float around the internet and scientific journals are to be valued. That people come away terrified ought to be entirely unsurprising. What is needed is a moral vision capable of surveying such a situation and finding reasons to throw ourselves "once more unto the breach, dear friends, once more".

Australian coal: A victory as one proposed coal plant is shelved.

Hunger games: Coming soon to a future near you. Future heat, drought, food costs and global unrest. I have long been saying that such secondary and tertiary effects of climate change are at least as dangerous as any direct physical effects, though they may not generate headlines that mention climate.

Planetary boundaries: "Approaching a state shift in Earth's biosphere", a recent paper in Nature includes this in its abstract: "Localized ecological systems are known to shift abruptly and irreversibly from one state to another when they are forced across critical thresholds. Here we review evidence that the global ecosystem as a whole can react in the same way and is approaching a planetary-scale critical transition as a result of human influence."

Solastalgia: The word is a neologism coined by psychologist Glenn Albrecht in 2003 and is gaining some recognition. It refers to nostalgia one feels for a place being lost even while you're still there, a homesickness while you're still at home, but home is becoming less hospitable. In Albrecht's own words, it is "emplaced or existential melancholia experienced with the negative transformation (desolation) of a loved home environment". I think it is a useful concept, even if I'm not convinced by the etymology.

Extreme weather: Extreme heat events experienced in many places in recent years are very, very unlikely to be unrelated to climate change. A new study by James Hansen on the attribution of extreme weather events does not use models, but is a statistical study based on observed changes that argues that the increase in what used to be extreme events (three standard deviations above the 1950-80 average) to now cover something like 10% of the globe's surface at any given time (rather than about 0.1% during 1950-80), is strong evidence that such events are vanishingly unlikely to not be related to climate change.

Overheated economy: Temperature rises correlate with declines in economic indicators and political stability, at least in developing nations. Good thing we're not expecting any discernable pattern in global temperatures over the next few decades and centuries then.

The West in Flames: The US West and Southwest is projected by most climate models to get hotter and drier. This has all kinds of implications, but this article by the author of A Great Aridness summarises the implications for trees and wildfire. It's not pretty.

400ppm CO2: Last time CO2 levels were this high. A study investigating conditions 15 million years ago found that "The last time carbon dioxide levels were apparently as high as they are today — and were sustained at those levels — global temperatures were 5 to 10 degrees Fahrenheit (2.8-5.6ºC) higher than they are today, the sea level was approximately 75 to 120 feet (22.9-36.6m) higher than today, there was no permanent sea ice cap in the Arctic and very little ice on Antarctica and Greenland".

US abandons 2ºC target? No, but it's still almost impossible under current assumptions

UPDATE: It seems my original headline and intro jumped the gun, at least on official US policy, relying on a secondhand and partial reading of the speech in question. My apologies. The rest of the post still holds and the paralysis of the US political system remains one of the largest roadblocks to any reasonable climate outcome.

The Obama administration has now abandoned the one piece of significant agreement to have come out of seventeen rounds of international climate negotiations, namely, the idea that the world was committed to aiming to keep warming below 2ºC. This temperature rise refers to the global average surface temperature's rise above pre-industrial levels* and covers a wide range of actual average temperature changes (and an even wider range of changes in temperature extremes) in various locations.
*Some documents use other baselines, such as the "climatological period" i.e. 1950-80, or even more recent periods of three decades. It is important to note whether a given temperature rise is based on pre-industrial baseline or a more recent one. Since temperatures rose by around 0.5ºC between the pre-industrial period and 1950-80 (and more since then), then discussions of future rises need to be adjusted accordingly. International negotiations have generally used the pre-industrial period as a baseline, even though the precise global temperature figures are a little sketchier.

The idea that 2ºC is a "safe" guardrail has a complex history, but it is fair to say that more recent climate science has shifted our understanding of just how dangerous 2ºC is. The expected impacts that were thought to arrive at 2ºC back when it was first established as something of a de facto line in the sand between safe and dangerous climate change are now expected to arrive much sooner, at somewhere between 1 and 1.5ºC. So if the developing consensus ten or fifteen years ago was that impacts associated with 2ºC were a valid danger limit, then really, if we are going to be honest and keep our judgements about what is dangerous, we ought to think that anything much above 1ºC is dangerous.

Unfortunately, going well beyond 1ºC is already guaranteed due to inertia in the climate system. What the US has now publicly acknowledged is what has been widely known for years - that inertia in the political and economic system has rendered 2ºC impossible within current economic and political assumptions.**
**The extent to which decades of failure from US leadership on this issue has rendered such a target politically impossible ought not to be underestimated. Despite featuring prominently in his campaign and inauguration, since coming into office, Obama has barely mentioned it and now puts out ads in support of coal.

To this, I say, "so much the worse for those assumptions". But the status quo would not be the status quo if it didn't try to protect itself from having to change. Unfortunately, climate change by definition rules out the possibility of no change. Our current trajectory is inherently unsutainable, which doesn't mean that polar bears are threatened by it, it simply means it will be not be sustained. Something must give. I would rather that be our political and economic assumptions than the habitability of the planet for as many generations as we can imagine.

We are on track for 4ºC if all nations stick to their current aspirational targets, and something more like 6ºC on our current trajectory, according to the normally conservative IEA. Professor Kevin Anderson, director of the Tyndall Centre for Climate Change in Britain, says that a rise of four degrees would likely be "incompatible with organized global community, is likely to be beyond 'adaptation', is devastating to the majority of ecosystems and has a high probability of not being stable (i.e. 4°C would be an interim temperature on the way to a much higher equilibrium level)." No one really knows what six degrees would mean, though sober-minder scientists start discussing human extinction as more than a theoretical possibility.

So, who's happy with six degrees? No takers? What about four degrees? Professor Hans Joachim Schellnhuber, Chair of the German Scientific Advisory Council, advisor to the German Chancellor Angela Merkel and Director of the Potsdam Institute for Climate Impact Research (PIK) was quoted back in March 2009, saying that on a four degree world the planet’s "carrying capacity estimates [are] below one billion people." So, who's happy to retain our present political and economic assumptions that make 2ºC seem impossible?

Basically, even with our best efforts, on the most optimistic path possible, we are in serious trouble. Facing these realities means shock, grief, fear, anger, guilt and feelings of helplessness. But until we face our situation honestly, we're living a lie. So let us be honest, grieve and then find reasons to fight even a losing battle.

Our climate challenge in three numbers

"When we think about global warming at all, the arguments tend to be ideological, theological and economic. But to grasp the seriousness of our predicament, you just need to do a little math. For the past year, an easy and powerful bit of arithmetical analysis first published by financial analysts in the U.K. has been making the rounds of environmental conferences and journals, but it hasn't yet broken through to the larger public. This analysis upends most of the conventional political thinking about climate change. And it allows us to understand our precarious – our almost-but-not-quite-finally hopeless – position with three simple numbers."

- Bill McKibben, Global Warming's Terrifying New Math.

Apart from missing "s" in the title and a dodgy stat in the opening paragraph, McKibben's compelling 5-page piece is a good summary of some important elements of the challenge we face. The bottom line of his three numbers is that, according to our best understanding, if we want at least an 80% chance of staying under the internationally agreed (but still very dangerous) 2ºC limit we can only burn about 20% of our current fossil fuel reserves (not resources, but reserves, i.e. what is known and could be profitably brought to market under present conditions). This is the kind of statistic that can really serve to focus the attention. We need to leave four out of every five known and already profitable barrels of oil, tonnes of coal, cubic metres of natural gas underground.

Of course, the great difficulty is that no one country wants to do anything other than burn every last molecule of fossil hydrocarbon that can be brought to the surface unless all other countries agree to limit themselves also. And when some countries have far larger reserves (and so far more at stake economically in leaving 80% of them in the ground), then reaching such an agreement is basically impossible under present political assumptions. If you look at where the blockages in international negotiations are coming from, then it's no great surprise that these are also the countries with the largest reserves of fossil hydrocarbons: China, USA, Russia, Australia, Canada, various middle eastern states. Countries with tiny (or largely depleted) reserves are the ones at the forefront: small island nations, non-oil-based African nations and the EU (esp UK and Germany, which have historically had huge fossil carbon deposits, but have already burned most of their easily accessible stuff).

And so we are left with an international multi-player game of chicken, with no country wanting to blink first and lose market advantage, ensuring that all countries suffer horrendously as a result. The fact that those with least to contribute to the problem generally have greater vulnerability only serves to entrench both the injustice and the intractability of the issue.

The slim silver lining in recent extreme weather in the US is that it might bring home to US voters and policymakers that there are no winners in a game of chicken. Even if others are going to suffer more and sooner, the US is far from immune, especially to precisely these kinds of threats (droughts, wildfires, heatwaves, water stress). Russia is facing its own wildfires and floods. China has had large areas in drought almost constantly for the last five years and a flood this week has a death toll that could pass 100. Canada has simultaneously faced deadly floods and serious drought in the last couple of months. Middle Eastern petro-states are all too aware of their dire water situation as they rapidly go from grain exporters to zero wheat production within a decade (Saudi Arabia) after basically exhausting their fossil water. And Australia has all too quickly forgotten its own droughts, bushfires and floods just a couple of years ago.

Further complicating the picture is that it is not simply countries that are making these decisions. Apart from some nationalised oil companies, most of these reserves are held by for profit corporations with very, very deep pockets and who are generally not shy at throwing their weight around, spending up big on lobbying, misinformation and propaganda at every level in order to convince us all that without them we'd be living in caves and that they are struggling to get by in tough conditions.

Yet according to the most recent data, fifteen out of the thirty most profitable companies in the world are directly fossil fuel related (many of the remaining fifteen also have significant, if slightly less direct, links).

1. Gazprom: US$44.5b
2. Exxon Mobil: $41.1b
4. Royal Dutch Shell $30.9b
5. Chevron: $26.9b
8. BP: $25.7b
11. Vale: $22.9b
12. Petronas: $21.9b
13. VW: $21.4b
14. Ford: $20.2b
15. Petrobras: $20.1b
22. China National Petroleum: $16.3b
26. GE: $14.2b
27. Statoil: $14.1
29. Rosneft Oil: $12.5b
30. ConocoPhillips: $12.4b

The bottom line is that until a very wide audience grasps just how dire our situation is and starts to demand something different from our corporate and political leaders, then none of key climate numbers are likely to improve.

For me, the most telling number in McKibben's piece is the one that he doesn't mention. McKibben is an author with a string of respected publications about environmental and economic issues. He was the first popular writer to publish a book on climate change back in the 80s. Yet in the last three or four years he has re-invented himself as an activist after becoming convinced that writing alone is too slow to effect the changes that need to happen. He has built and become the public face of the world's largest climate movement, a movement named after and dedicated to a number: 350. His organisation, 350.org, refers to the highest concentration of CO₂ in parts per million considered "safe" by some of the world's leading climate scientists. We are currently over 390 ppm and rising rapidly. For most commentators, 350 ppm is seen as a pipe dream, an impossibility, well outside the realm of the thinkable, let alone the achievable. International negotiations talk about 550 and occasionally 450, but many commentators think we'll be lucky to stay below 650 and our current path is heading for 750 or significantly higher. In this context, McKibben and 350.org have served as a witness to how far from a just and sustainable world we are currently travelling. And yet here, in one of his highest profile pieces to date, he doesn't mention the number to which he has dedicated the last few years of his life and of which he is a relentless promoter. Is this because he has been so successful in publicising 350 ppm that he felt he could move on? Or because he decided that this idea is now so detached from reality that he needed to lower his sights?
Image by ALS.

Graphs can be terrifying: Getting a grip on CO2

H/T Gareth.
This soundless little presentation from NOAA's Carbon Tracker shows atmospheric carbon dioxide (CO₂) concentrations over time. The first half of the video shows on the left hand side the yearly rise and fall of CO₂ concentrations around the world since 1979. The various dots along the line each represent a different location around the globe, arranged by latitude, with the blue dot on the far left being the south pole and the dots at far right representing measurements in the Arctic. The dots rise and fall in a regular pattern as time passes. This is because trees "breathe in" CO2 during the northern spring/summer as leaves photosynthesise and then "breathe out" in autumn/winter as leaves decay, meaning that atmospheric concentrations rise and fall a little each year in a natural cycle. The annual variations are far more pronounced in the north hemisphere (the right end of the line that bounces up and down) since there is a much greater mass of land (and so trees) up here than in the southern hemisphere. So the concentration is never exactly the same at every point in the world or on every day of the year. And yet, along with the annual cycle there is something else happening. The overall movement is unmistakeable: up, up, up. If we look at the right hand side of the display, which shows the famous "Keeling curve" of average CO2 concentrations going back to 1958 when precise records first began to be kept (by Prof C. D. Keeling at Moana Loa in Hawaii), we can see that the annual rise and fall of the natural carbon cycle is superimposed on and ultimately dwarfed by a relentless upwards rise, which represents the human contribution to the situation. Each year we dig up literally billions of tonnes of carbon that had been safely stored for millions of years underground and burn it to power our lightbulbs and laptops, our concrete and cars, our fridges and flights.

Once the period 1979-2011 has been shown (up to about 1:40 in the video), we begin to zoom out, seeing further back in time. Initially, we are introduced to the earlier progress of the Keeling curve as it wobbles up and down back to 1958 (the green part of the cuve, spanning roughly 1:40-2:00 in the video). Then we suddenly begin zooming out much more quickly, and the green curve becomes a series of yellow dots spanning back to the time of Christ (2:00-2:20). Since the apostles were not measuring CO₂, these measurements are "proxies", reconstructions of historical concentrations from a wide range of sources that have preserved a natural record of atmospheric concentrations. From 2:20-3:00, the blue curve represents a record of pre-historic CO₂ concentrations going back 800,000 years (ka = thousand years; BCE = Before Common Era = BC) preserved in the ancient sheets of Greenland and Antarctica (Antarctica has the deepest ice and so the oldest records). The line here jumps up and down over many thousands of years as the world went into and out of glaciations (commonly, though incorrectly, known as "ice ages"). When CO₂ concentrations were low (below 200 ppm), huge sheets of ice covered vast areas of land in the northern hemisphere. We have very good reasons for believing that CO₂ concentrations played a crucial (though not exclusive) role in previous natural changes in climate.

The units used to measure CO₂ concentrations are parts per million (ppm), that is, the the y-axis (vertical axis) represents the number for CO₂ molecules for every million molecules of gas in the atmosphere, so 300 ppm means 0.03% of the atmosphere was CO₂. These seem like tiny amounts and it is true that CO₂ is a trace gas, but the effects of even small changes in some trace elements can be very large. If we were adding arsenic to a cup of coffee, then a mere 300 ppm would be sufficient to kill you. So don't be fooled by those who point to the "small" numbers involved. Changing the CO₂ concentration from 280 ppm (as it was prior to the Industrial Revolution) to today's level of approximately 395 ppm represents the addition of more than a trillion tonnes of carbon dioxide.

So what does this all mean? This presentation very usefully shows the very large natural atmospheric changes in the earth's "recent" experience (recent by geological standards, since the earth itself is 4.5 billion years old). Notice that the difference between glaciers thousands of metres thick covering most of the UK and more temperate periods during which life can flourish on these isles was only about 100 parts per million.

Human agriculturally-based civilisation has only existed in the most recent 10,000 years (known as the "Holocene"), during which time CO₂ concentrations (and so climate) have been fairly stable. Or had been.

So what we see (or is at least hinted at) in this video is (a) the ability of relatively "small" changes in a trace gas like CO₂ to produce huge, world-changing effects on climate, (b) the relative stability (CO₂ and climate-wise) of the period during which human civilisation has developed and (c) the dramatic and very sudden jump in CO₂ concentrations during the last 150 years or so, accelerating rapidly over the last six decades. Compared to all previous changes, the rate of change we're seeing is off the charts. In comparison to even the steepest rises and falls during glaciations and de-glaciations, the last century or so has been basically a vertical rise, almost the equivalent of a de-glaciation in the blink of an eye. And we're already in uncharted waters, at concentrations not seen for at least 800,000 years (indeed other proxies that go back even further - albeit with lower levels of confidence - suggest that CO₂ concentrations have not been this high for at least 20 million years). And if you look at the numbers on the y-axis, keep in mind that our current trajectory, in the absence of either global economic collapse or a massive energy and/or cultural revolution, will take us above 800, 900 or even 1,000 ppm during my daughter's expected lifetime. We ain't seen nothing yet.

And carbon, once removed from the stability and safety of underground storage, sticks around in the oceans, atmosphere and soils (the "active carbon cycle") for a very long time. We'll see elevated levels of carbon for hundreds and even thousands of years after we reduce human emissions to zero. It's important to keep clear in your mind the difference between emissions and concentrations. Emissions are like income going into your bank account, concentrations are like your account balance. So if we get to a concentration of, say, 700 ppm and decide to go on a crash diet of zero emissions, things won't return to "normal" for tens of thousands of years.
One recent study pointed out that CO₂ released by pre-industrial deforestation continues to affect climate today, albeit on nothing like the scale of industrial activities.

Why is this a problem? Many serious and senior researchers believe that life as we know it is incompatible with CO₂ concentrations above 450 ppm. In the long run, many think that anything over 350 ppm is too high since 450 ppm could well trigger the extinction of literally millions of species, perhaps a third of all those currently on the planet. Remember, we're currently at about 395 ppm and rising by more than 2 ppm each year.

Yet the insidious thing is that the effects of elevated CO₂ concentrations are not immediately apparent. It can take decades for global temperatures to respond to shifts in atmospheric composition, centuries before the full effects are visible and millennia before sea levels will stabilise. So that means the crazy shifts we're already seeing are merely the result of where CO₂ concentrations had reached back in about 1980 or so. Even with the best efforts, things are going to get worse for some time after we start taking this problem seriously. Thus any generation that chooses to forgo the seductive and wondrous benefits of fossil fuels will not immediately reap the rewards. We can always kick the can down the road for a few more years, but in doing so, we condemn our children (and their children and as many generation as we can imagine) to an increasingly hellish existence.

People and Planet: a new report and other stories

Royal Society report (Summary and recommendations) calls for both population stabilisation and big cuts in consumption to avoid "a downward spiral of economic and environmental ills". This is a significant contribution to the discussion of the relationship between population and consumption (which I discussed back here). I haven't had a chance to read the full report yet, but the conclusions seem to be broadly consistent with the points I made: that both population and consumption need to be addressed, but the latter can be addressed faster, further and with fewer ethical conundrums and so ought to be the primary immediate focus.

Guardian: IEA warns of 6ºC rise. It is hard to get a handle on just how catastrophic 6ºC would be. Let's just say that if we get to 6ºC, I don't think we'll be doing cost-benefit analyses anymore. David Roberts reflects on whether 6ºC is alarmist or realistic and points out that science alone can't tell us how bad climate change will be - because the most important unknown is just how we are all going to act and react over the next couple of decades. Those who think that 6ºC by 2100 is entirely unrealistic implicitly assume either (a) massive global co-ordinated action to mitigate through aggressive emissions reductions across the board or (b) global and long term economic collapse arriving sooner rather than later.

Mongabay: Organic agriculture has lower yields than industrial farming, according to a new study in Nature, especially for grains, though that is not the whole story, since there are various downstream costs of industrial agriculture that reduce yields elsewhere (and elsewhen).

ScienceDaily: Plastic in ocean underestimated by at least a factor of 2.5 due to the effects of wind pushing pollution beneath the surface, rendering measurements and calculations based on skimming the surface inaccurate.

SMH: India's border fence. Not with Pakistan or China, but the 4,000 km militarised fence on the border with Bangladesh, in the face of a rising tide of people fleeing, amongst other things, a rising tide. Though speaking of that rising tide...
H/T Donna.

ABC: Australasia at hottest for (at least) 1,000 years (also in the Guardian and the original study is here). This is a significant finding since most temperature reconstructions have focused on the northern hemisphere, where a greater number of proxy records mean more data is available.

Science: Some good news from Greenland. A review of ten years of satellite data appears to indicate that we are not on track for the "worst case" (i.e. 2 metre) sea level rise by 2100. Of course, "good" is relative; even a rise of a few feet will lead to massive headaches, but multi-metre rises probably mean infrastructure vulnerabilities worth trillions. Sea level rise is one of the most serious long term effects of climate change, though I suspect that over the next few decades it is not going to dominate in comparison with, for example, concerns over food security.

Grist: What would it look like for media to take climate seriously? A very interesting conversation between two journalists about media coverage of the climate threat.

130 Years in 30 seconds

The changes displayed in this video represent average global surface temperatures warming by about 0.8ºC over a period of 130 years. On our current path (including current national and regional agreements to reduce emissions), we are heading towards something like five times that change in the next 90 years.

It doesn't have to be this way.
Original source with further commentary at NASA.

So long and thanks for all the fish

I recently came across this summary of the state of the world's marine life after decades of industrial scale pollution, warming, acidification, trawling, nutrient runoff and overfishing. It is from this paper.

Jesus and climate change (series links)

Some time ago, I published a series ambitiously titled "Jesus and climate change". It was basically the text of a talk I gave once or twice. I've just realised that I never posted a series of links to be able to find parts of it more easily. I would probably approach a talk like this a little differently now, and I've certainly learned a great deal more about climate in the meantime, but the last six posts are not a bad exposition of some of my basic theological convictions that remain important to me today. The highlights are probably XIII and XV.

I. Introduction and a caveat concerning scepticism
II. What's happening?
III. Discussion questions
IV. Why God cares - it's his world
V. Seeing Creation
VI. Matter matters
VII. Alternatives to Creation: a brief tangent
VIII. But what's the problem?
IX. Guilt and fear
IX(b). So what's God doing about it?
X. Jesus' life: God with us
XI. Jesus' death: liberation
XII. Jesus' resurrection: renovation
XIII. The renewal of all things
XIV. But what's God doing now?
XV. Conclusion: what does the church have to do with climate change?

Take the mic away from the speakers...

Here's another climate feedback: More frequent and severe heat waves, such as the one breaking all kinds of records in the US at the moment, are one of the most likely effects of continued climate change. More severe/frequent heat waves mean higher peak electricity demand, which means more power stations being built, which means more capacity in the system, which means more impetus to use it, which means (barring widespread and rapid implementation of cleaner energy) more greenhouse gas emissions, which means - well, you get it by now.

On track for 4ºC

At Copenhagen in 2009 and then once more in Cancún in 2010, the nations of the world agreed on the goal of limiting global warming (the most talked about part of climate change and a rough indication of the overall severity of change) to a rise in average surface temperature of no more than 2ºC above pre-industrial levels. We are already almost 0.8ºC up, with something like another 0.5ºC already committed due to the time lag between emissions and their effects. To have a 75% chance of keeping overall warming under 2ºC by 2100 would require us to emit no more than a trillion tonnes of carbon dioxide between 2000 and 2050. How much is a trillion tonnues? Well, simplifying matters somewhat, and given that we've already used a fair chunk of that, the bottom line is that it woud require us to leave more than half of the economically recoverable fossil fuels (oil, coal, gas) in the ground. That is: no more searching for new fields; no further exploitation of the non-conventional sources (shale gas, tar sands, methane hydrates); no inclusion of fields currently too expensive to exploit. And we leave more than half of what is already known and can already be removed profitably in the ground.
Those interested in the fine print of the numbers used in these calculations can consult this quite technical study.

Two degrees would still bring all kinds of very undesirable consequences. It would be likely to mean virtually no summer sea ice in the Arctic, the loss of most coral reefs around the world, potentially dramatic declines in total ocean productivity (at least as far as fish are concerned; jellyfish may do quite well), the eventual extinction of hundreds of thousands or even millions of species, significant suppression of total global crop yields (when total food demands are likely to double by 2050), sea level rises of 50-100 cm by 2100 and of many metres over the coming centuries, changes in precipitation patterns leading to both worse droughts and floods, a more fragile Amazon and already the possibility of passing thresholds that could precipitate sudden and irreversible changes. Two degrees is no walk in the park.

While the world agreed that 2ºC ought to be treated as an upper limit (except low-lying island nations, for whom 2ºC would already likely be a death-sentence), the pledges made as a result of these negotiations put us on track for a world that is more likely to be around 4ºC warmer by 2100, and more than 6ºC warmer during the following century. Note that these pledges are in some cases aspirational and lack any legislative framework to accompany them. In Australia's case, our pledge (lying quite firmly at the less ambitious end of the scale) is dependent upon the implementation and success of the Gillard government's proposed scheme to put a price on carbon. So even were we (and all other nations) to implement successfully our plans, we are still far more likely to be at 4ºC by 2100 than anywhere near 2ºC.

If a 2ºC world sees us suffering from a wide range of very difficult and worsening challenges that will stretch our ability to cope, a 4ºC world would be unrecognisable. A conference this week looking at the likely impacts on Australia of a four degrees rise suggested that Australia, the world's sixth largest food exporter, may no longer be able to feed itself. The difficulty of understanding just how different such a world would be is illustrated by the following quote from Professor Hans Joachim Schellnhuber, Chair of the German Scientific Advisory Council, advisor to the German Chancellor Angela Merkel and Director of the Potsdam Institute for Climate Impact Research (PIK). In March 2009, Schellnhuber said that on a four degree world the planet’s “carrying capacity estimates [are] below one billion people.”*

Just let that sink in.

Or find ways to avoid thinking about it.
*Carrying capacity is a complex and contested notion and obviously depends on a range of assumptions about average standard of living. The point is not to suggest that one billion is a fixed limit, but simply to highlight how severely compromised the systems on which we rely for a world of seven billion people may be in a four degrees warmer world.

UPDATE: Kevin Anderson, until recently the director of the U.K.’s leading climate research institution, the Tyndall Energy Program, had this to say about four degrees: “a 4 degrees C future is incompatible with an organized global community, is likely to be beyond ‘adaptation’, is devastating to the majority of ecosystems, and has a high probability of not being stable.”

Incompatible with an organised global community. Parse that how you will, it ain't pretty.

A white Christmas in a warming world

The answer to Wednesday's riddle ("what has six arms, can swallow farms and a million makes a man?") was snowflakes.

At the end of last month, I raised the question many people in the UK are asking at the moment: where did the global warming go? It started snowing in November and here in Edinburgh there have been numerous significant falls over the last three weeks, with snow continuously on the ground the whole time. I've lost count of the days that have dropped below -10ºC and only one or two have nudged above freezing. Transport in the UK has been thrown into chaos, with trains cancelled or delayed, roads blocked, airports disrupted. Heathrow airport, the largest in the world, was closed or running at reduced capacity for much of the last week.*
*This affected us personally since my sister, who was here visiting us until yesterday, was very unsure whether she would be home for Christmas with her husband and children. As it turned out, her flight from Edinburgh to Heathrow was cancelled, and the train which she took instead was delayed by three or four hours, but she managed to get home.

So far, it is shaping up to be the coldest UK December on record, running about 5ºC below average. The last three years have all been significantly colder than average. Prior to that, the trend was for warming winters, which was quite consistent with the widespread scientific understanding anthropogenic climate change, which predicts more warming at night, at the poles and during winters (all patterns evident in the temperature record and which rule out solar forcing as the main culprit). Indeed, only a couple of years ago, the MET Office infamously predicted, "Children just aren't going to know what snow is". So what happened?

I suggested back in November that a pattern of WACCy weather (Warm Arctic Cold Continents) might help us understand this phenomenon. Where did the warming go? The UK is five degrees colder than usual, but much of Greenland is up to 15 degrees warmer than the long term average, and large parts of the Arctic Ocean are more than 10 above average. Indeed, recent studies suggest a link between declining Arctic sea ice and patterns of cold air for the continents in northern latitudes. With less sea ice over the Arctic ocean, more heat escapes from the water (which is obviously no colder than 0ºC) to the atmosphere (which is, as one would expect during an Arctic winter, generally well below zero). This creates high pressure cells, which disrupt the usual wind patterns and lead to the much-warmer-than-usual-but-still-freezing Arctic air being pushed further south over the continents. When this freezing air coming down over the UK runs into moist air being brought from the Atlantic, we get significant (by UK standards) dumps of snow, bringing the country to a standstill.

All this has been mentioned numerous times in scientific papers and reports from NOAA and NASA (and again), but has barely rated a mention in most mainstream media (Monbiot is a notable exception).

Is this having one's cake and eating it if both warmer and colder winters are evidence of climate change? No, because climatologists have never claimed that every place would be affected in the same way at the same time. Global warming is (a) global and (b) only one of the effects of climate change. Climate change means climate disruption, increasingly dramatic shifts from the relative climatic stability of the Holocene that has nurtured the birth of agriculture and the rise of human civilisation over the last ten thousand years or so. Is using the term "climate change" in preference to "global warming" a con to save face? Not at all, since the terms mean slightly different things and both have been in use for decades. (Or if you'd prefer, here's a video response.)

It is not yet clear whether this pattern is likely to become the new normal UK winter as Arctic sea ice continues its apparent death spiral, or whether other factors will prove more significant. On that question hang billions of pounds in infrastructure decisions.

And so tomorrow in Edinburgh, there will probably be snow on the ground for Christmas: a white Christmas in a warming world.*
*I realise that, technically, bookmakers and the MET Office define a white Christmas as at least a single snowflake reaching the ground somewhere in the UK, but snow on the ground is good enough for this Aussie.

Where did the global warming go?

Despite the amazing snow we've been getting in Edinburgh, globally this year is currently tied in first place and is on track to be at least in the top three hottest years on record. More national highest temperatures have been set this year than any previous year. Indeed, ironically the impressive snow (by local standards) received in the UK this year and last year is linked to unusual wind patterns in the Arctic creating a phenomenon dubbed "WACCy weather" - Warm Arctic Cold Continents. Warmer temperatures in the Arctic and over Greenland block the prevailing westerly winds and instead lead to frigid air descending on the UK from the north and north-east.

The Arctic climate is warming faster than anywhere on earth so we might well see more of this pattern in future. This is why it is important to think in terms of climate change and not simply global warming (which is one, often misunderstood, feature of climate change).

Why does this matter? Because within my daughter's lifetime (if she manages to stay healthy), our current climate trajectory could well lead to a billion people losing their homes and three billion losing access to clean water. On our current path, we are headed well beyond a rise of 2ºC and to more than 4ºC by the end of this century, which is likely to mean droughts beyond anything in human memory covering large parts of the globe while other parts flood, millions of refugees, dire crop reductions and the social and political instability these would likely bring.

"In such a 4°C world, the limits for human adaptation are likely to be exceeded in many parts of the world, while the limits for adaptation for natural systems would largely be exceeded throughout the world."

- Rachel Warren, “The role of interactions in a world implementing adaptation and mitigation solutions to climate change”, Phil Trans R Soc A 13 January 2011 vol. 369 no. 1934 217-241.

It doesn't have to be this way.

On the attribution of extreme weather events

"Finally, a comment on frequently asked questions of the sort: Was global warming the cause of the 2010 heat wave in Moscow, the 2003 heat wave in Europe, the all-time record high temperatures reached in many Asian nations in 2010, the incredible Pakistan flood in 2010? The standard scientist answer is 'you cannot blame a specific weather/climate event on global warming'. That answer, to the public, translates as 'no'.

"However, if the question were posed as 'would these events have occurred if atmospheric carbon dioxide had remained at its pre-industrial level of 280 ppm?', an appropriate answer in that case is 'almost certainly not'. That answer, to the public, translates as 'yes', i.e., humans probably bear a responsibility for the extreme event."

- James Hansen, "How Warm Was This Summer?" from NASA Goddard Institute for Space Studies.

The whole piece is worth reading, not least for the prediction that 2012 is "likely" to reach "record high global temperatures", after 2010 has already repeatedly broken the twelve month running average (temperatures in 2011 are likely to be slightly suppressed from record levels by the La Niña that has developed in recent months). I also talked about the difference between weather and climate back here.

Dr James Hansen is the head of NASA GISS and was the first academic to bring climate change into mainstream awareness at his US congressional testimony on 23rd June 1988, which became front page news when he claimed there was sufficient evidence to give 99% certainty that "It is already happening now".

As you may have noticed, Hansen takes his duties as a citizen (and grandfather), as well as a scientist, seriously. Last week Dr Hansen was arrested (once again) for civil disobedience while protesting coal mining through mountaintop removal, which manages to combine a whole raft of destructive effects on the way to disrupting the climate.

Here is another quote on attribution worth pondering:

"The point is that while it is a perfectly reasonable question to ask: “Was this event due to climate change?” it would more useful to ask a related question: “are we putting ourselves at greater risk of experiencing this kind of event?” And to that scientists can answer with high confidence: yes!

"Now, you might think this question is less interesting or useful, and perhaps not as worth asking than the first one. But we would argue that, in fact, it is very important to pose this question, and to carefully consider its answers.

"Think of smoking, sun bathing without sunscreen, eating lots of junk food and so on. You may not be able – ever – to unequivocally attribute one person’s problem to the effects of these activities: people develop lung cancer without smoking, for example, but as a population we know we are better off wearing sunscreen, watching our cholesterol, and not smoking, since all of these actions have been shown to make the chances of harm to our health lower."

- Nicole Heller, Claudia Tebaldi, and Phil Duffy, "Why Can’t Scientists Say the Recent Extreme Weather Events Are ‘Proof’ of Climate Change?" at Climate Central.

And then there were 306...

NOAA: “August 2010 was the 306th consecutive month with a global temperature above the 20th century average. The last month with below average temperatures was February 1985.” Any day the temperatures for September will be in. It's a safe bet to expect they will make it 307.

The most commonly cited target in international climate negotiations is that we ought to limit warming to an average of 2°C. However, that may already be too high.

How to shrink a city: this will become an increasing issue in many parts of the world due to likely demographic and economic changes of the next few decades.

Peak oil and healthcare, a UK perspective.

Terminological clarification: irreversible vs unstoppable.

Hot Topic: On giving up non-essential flying.

The health benefit of more ambitious emissions targets. If Europe raised its sights from 20% to 30% emissions cuts by 2020, then it could be saving an extra €30 billion per year in health costs. This saving alone would account for a significant portion of the estimated €46 billion p.a. the higher target would require.

Twenty-two percent of the world's plant species are threatened with extinction and another thirty-three percent have an unknown status. The main culprit? Land use changes associated with agriculture.

Rivers in peril worldwide: study in Nature claims that eighty percent of the world's population (nearly 5.5 billion people) lives in an area where rivers are seriously threatened. "[S]ome of the highest threat levels in the world are in the United States and Europe." See also here a graphic of the threat distribution.

Oceans acidifying much faster than ever before in Earth's history.

Soil degradation, erosion and desertification continues in many places around the world, reducing the amount of arable land.

On average, every single man, woman and child on the planet is US$28,000 in debt.

Speaking of money, a new study has estimated that the cost of vanishing rainforest each year is approximately US$5 trillion (with a "t". i.e. US$5,000,000,000,000).

However, the real issue is that each of these crises are not isolated, but are all converging on similar time scales.

Choking on coal

Washington Independent: coal related health effects cost the US $100 billion each year, including over 13,000 deaths. I imagine that even prior to considerations of climate change, if the public health effects of burning coal are taken into account, renewable energy is more affordable than such dirty combustion. Meanwhile, the head of BHP Billiton has said that Australia needs to move beyond coal. And finally, images of coal ash in China.

Independent: UK government to adapt to inevitable warming, yet without spending any more money.

Mongabay: Amazon.com vs the Amazon: paper trails and deforestation.

Deep-sea trawling damages an area twice the size of the contiguous USA each year.

And just to show that sometimes simultaneous disasters can dilute rather than amplify each other: Scientific American reports on research showing that hurricanes help save thermally-stressed coral reefs by cooling water temperatures; Skeptical Science points out that in New York, higher rainfall doesn't necessarily mean more flooding due to drier soil from higher temperatures; and NASA satellites reveal that the incidence of wildfires is no higher in dead forests killed by mountain pine beetle infestations (which have reached epidemic proportions due to warmer winters enabling more beetles to survive) since green needles of live trees are more flammable than brown needles of dead ones.

These points vaguely remind me of the story of a man who wanted to kill himself and so decided to do a thorough job. He hung himself over a lake after taking poison and brought along a gun to make sure. His shot missed his head and severed the noose, dropping him into the water which diluted the poison. Since all the other methods had failed, he decided he wanted to live after all and so swam to shore and survived. I'm not sure we're going to be so lucky.