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.

Glimmers in the gloom: 10 signs of climate progress

It is easy (and pretty apt) to get depressed about the climate situation. As records keep tumbling and feedbacks kick in and polluters continue to throw their political weight around, the momentum on our trajectory into ever greater disaster can feel overwhelming. Yet it is also apt at times to remember some glimmers of good news amidst the gloom. Here are the ten signs that most encourage me about places where progress that has been made since this image was taken a handful of years ago.

•  In five years, the value of the four largest US coal companies has plummeted from $45b to $200m, a drop of more than 99.5%. A string of major financial institutions have declared the coal industry to be in structural decline.

• For the last two years, China has reduced its coal consumption without being in recession. This included shutting down hundreds of smaller, dirtier coal mines.

• For the last few years, new renewable electricity generation capacity has exceeded new fossil fuel + nuclear capacity. Both wind and (especially) solar have seen their costs drop dramatically in the last 5-7 years.

• ExxonMobil faces the possibility of real legal consequences for their decades of lies and misinformation. And by extension, other fossil companies too.

• Fossil fuel divestment continues to expand rapidly, with now trillions in funds under management having divested in part or whole, or having committed to doing so.

• Mass civil disobedience against the causes of climate disruption is increasingly becoming a reality. Australian efforts such as the #LeardBlockade and #PilligaPush and #BentleyBlockade and #LockTheGate have seen the largest campaigns of civil disobedience since the Franklin River in the early 80s.

• Leaders with large followings in the UK and US are speaking openly and repeatedly about corruption, plutocracy, inequality and corporate hegemony - and drawing the links to climate change.

• Public opinion in the English-speaking world on the need for taking climate action is at its highest for almost a decade. While fickle and related most closely to recent weather as much as anything else, this nonetheless presents new opportunities.

• The compromised and weak Paris Agreement nonetheless represents the most ambitious step forward in international negotiations thus far, with every nation signing on to the need to participate in emissions cuts to keep warming to less insane levels.

• The US Republicans - the only major party in the developed world to embrace an official policy of climate denial - look increasingly likely to nominate an unelectable and divisive figure who could demolish their gerrymandered Congressional stranglehold on his way down.

• The most recent papal encyclical, Laudato Si', was a stirring call with implications that were nothing short of revolutionary, whose effects continue to reverberate throughout the global Catholic (and catholic) church.

And the final encouraging sign is that I sat down to try to write a list of ten and came up with eleven.

Climate and mental health

“People may, indeed, suffer from anxiety about climate change but not know it. They will have a vague unease about what is happening around them, the changes they see in nature, the weather events and the fact that records are being broken month after month. But they won’t be sufficiently aware of the source, and furthermore, we all conflate and layer one anxiety upon another.”

- "Climate Change is Wreaking Havoc on our Mental Health, experts say", The Star, 28th February 2016.

Living on a warming world is bad for your mental health. For climate scientists, environmentalists and those who have lived through climate-related extreme events, the impacts are often quite conscious. For many others, there is a deep unease lying not too far below the surface.

Awakening to climate change has affected my own mood considerably over the last eight or nine years. I have spent long periods of time depressed, angry, anxious and grieving. My thesis topic looking at emotional responses to climate change was prompted by both my own experience and the testimony of many people I know well who have started to take climate change seriously.

Finding resources to cope and reasons to keep going when we know worse is on its way will only become more important as the century progresses. My hunch has been that the gospel of Jesus, the community of the church and Christian practices of discipleship and spirituality may have a constructive role to play for some people. Not that these "cure" mental distress, but that they can shed new light on uncomfortable emotional experiences and keep open the possibility of creative action amidst bleak situations.
Image by Loic Venance (AFP/Getty Images). Waves breaks against a pier and a lighthouse during high winds in Les Sables-d'Olonne, western France, on February 9, 2016

Reform vs revolution: visions of social change

There is a dispute or tension at the heart of most attempts at addressing injustice: should we seek achievable incremental change to make a broken system slightly less damaging to those who are victims of its injustice or risk more ambitious change that attempts to shift some of the fundamental reasons for that injustice?

For instance, the recent Paris Agreement, viewed through the incrementalist model was an outstanding semi-miraculous success, yet viewed through the lens of justice, was a further entrenching of the power of the systems that have caused the problem and which show little inclination of doing anything like what is necessary to avoid suffering on a grand scale.

Expressing the latter perspective, Slavoj Zizek says (and I've never managed to discover if he is quoting someone else at this point), "the worst slave owners were those who were kind to their slaves", that is, some attempts at incremental improvements to the worst aspects of an unjust system can simply be part of maintaining that system by making it more palatable to the consciences of those who are the system's beneficiaries.

Yet a similar charge gets levelled against the idealists: by demanding more, the possibility of making real tangible improvements to the lives of suffering people is sometimes lost. Oliver O'Donovan praises the virtue of compromise, which means being willing to do "the best that it is actually possible to do", that is, to avoid making the best the enemy of the good.

But the tension here is not always destructive. We are not always necessarily faced with a choice between token improvements that inoculate against further change or demands for impossible systemic change that suck the energy from incremental reforms. Sometimes, strategic piecemeal reforms can help to express, build and solidify public opinion regarding values that ultimately lead to more ambitious changes. And sometimes, demands based directly in ideals reveal the truth of an injustice with a clarity that enables much-needed reforms to occur.

But the reason that this tension is perennial in all movements for change is that this dispute between reformers and revolutionaries cannot be decided a priori. In O'Donovan's language, "what is possible" is itself highly contested. Who is to say that what currently seems impossible might not become thinkable under the pressure of a sustained radical social movement?

Such judgements about what is indeed possible must be made according to close attention to the particulars of the situation, while also being informed by a vision of divine providence being capable of doing more than we ask or imagine; hard-nosed assessments of political openings must be combined with a strong sense of historical contingency, cultural malleability and the omnipresent possibility of repentance.

Put another way, reformers ought to be strategic in seeking reforms that will heighten rather than lessen the visible tension between reality and justice. Where there is a choice between improvements that tend to make the powerful feel more comfortable and improvements that help to further reveal the injustice of the present order, then pick the latter. And revolutionaries ought to articulate visions and select strategies based on a credible (if ambitious) path towards change, where the next step is comprehensible as movement on a journey towards justice.

Of course, this doesn't mean antagonism between reformers and revolutionaries will cease, or that all will agree on where the convergence between competing strategies might lie, but hopefully it can help in avoiding some of the more egregious dead ends.

So was the Paris Agreement a miraculous unprecedented step towards international cooperation or a woefully inadequate further betrayal of future generations and vulnerable lives everywhere that further reinforces the power of the perpetrators?

Your perspective probably reveals where you lie on the spectrum between reformer or revolutionary. For me: it is both.
Image credit unknown.

Personal and political: why cycling and recycling are insufficient

What can I do in response to climate change? As I talk to people about climate and ecology, I get asked this with great frequency, and this is not surprising. Previously, I've tried to put together a bit of a list of suggestions. Yet in replying to such a question, I often point out that "what can I do?" is a secondary question. More important than what I can do is what we can do.

Now of course there are indeed all kinds of things I can do to reduce my contributions to climate-altering emissions: buying less stuff, ditching the car, cutting flying, purchasing renewable energy, eating less meat and dairy and so on (note that recycling or changing lightbulbs, which are the usual answers people want to hear are way down this list, since they are relatively minor compared to some of the things here).

Personal footprint reductions are good, being: (a) simply the right thing to do in a world throwing away its habitable climate; (b) culture-shaping (normalising solar-installation, for instance); (c) economic communication to corporations (though this influence is plutocratic in effect, since it is one dollar one vote); (d) a talking point for persuasion (people ask questions); (e) an actual (albeit tiny) contribution to global emissions reduction; and (f) important for avoiding the all-too-easy charge of hypocrisy (this is one of the most common lazy defeater arguments people use to keep these issues at bay and it's powerful to be able to show how you're shifting your lifestyle).

But personal footprint reductions are secondary. On the timescales we have and with the structure of the problem locating particular power in massive fossil fuel interests to block progress (through corruption/regulative capture of the political authorities), it is critical that responsible action focus on cultural and political action. If we had a century in which to reduce emissions then personal lifestyle changes and a bottom-up cultural change would undoubtedly be the way to go. If we were not facing one of the richest and most powerful industries in history with a track record of shaping the political landscape to suit its agenda, then building a new and better alternative would be relatively straightforward.

Unfortunately, we don't have decades to start reducing emissions. A significant fraction of our emissions today will still be altering the climate in tens of thousands of years and we're already at the point where the observed changes (let alone those in the pipeline due to the temporal lag between emissions and warming) are becoming increasingly dangerous to human and natural systems. Two degrees warming is flirting with disaster; four degrees is a recipe for catastrophe. Our current trajectory is heading for four degrees or more. Every year we delay, the price tag of the necessary emissions reductions jumps by something like US$500 billion.

We're well past the stage where quietly changing a few lightbulbs is going to cut it.

This is one of the reasons why I am excited about the campaign to get individuals and institutions with a social conscience (churches, universities, city governments) to divest from fossil fuels. Divestment is not primarily an economic strategy, since my few dollars will always be dwarfed by the massive sums and inertia associated with business as usual. Divestment is a cultural and political strategy, changing the nature of what is normal and thinkable (i.e. culture) by putting fossil fuels into the same category as other "unthinkable" ways of making money (e.g. asbestos, tobacco, weapons, gambling, etc.), and in doing so, also changing the way that the political winds are blowing, repositioning the fossil fuel lobby to be as politically toxic (or more) than, say, the tobacco lobby. When politicians are embarrassed to be seen publicly with the fossil fuel lobby, we're winning; when they know they have to stop receiving all donations from them due to the political costs involved, then we've won.

At least round one.

An open letter from 200 evangelical scientists

Two hundred US evangelical scientists write an open letter to Congress calling for meaningful climate action. Here is a taste:

The Bible tells us that "love does no harm to its neighbor" (Romans 13:10), yet the way we live now harms our neighbors, both locally and globally. For the world's poorest people, climate change means dried-up wells in Africa, floods in Asia that wash away crops and homes, wildfires in the U.S. and Russia, loss of villages and food species in the Arctic, environmental refugees, and disease. Our changing climate threatens the health, security, and well-being of millions of people who are made in God's image. The threat to future generations and global prosperity means we can no longer afford complacency and endless debate. We as a society risk being counted among "those who destroy the earth" (Revelation 11:18).

Climate change prayer

Holy God,
earth and air and water are your creation,
and every living thing belongs to you:
have mercy on us
as climate change confronts us.

Give us the will and the courage
    to simplify the way we live,
    to reduce the energy we use,
    to share the resources you provide,
    and to bear the cost of change.

Forgive our past mistakes and send us your Spirit,
    with wisdom in present controversies
    and vision for the future to which you call us
in Jesus Christ our Lord. Amen.

©Anglican Church of Australia Trust Corporation. Used by permission This text may be reproduced for use in worship in the Anglican Church of Australia

Global warming over the last 16 years

A brief response to a common claim.

Fear and identity: the insufficiency of facts

Katharine Hayhoe - mother, evangelical Christian, pastor's wife and highly regarded professor in atmospheric physics - makes an excellent point. Climate change threatens more than ecosystems, economies and the stability of societies; it also threatens certain identities, and we often hold those even closer than our children's future.

Burden of proof

Yes, 0.1% = 1 in 1,000, not 1 in 10,000. But otherwise, amen.

Scotland: world's greenest nation?

For all kinds of reasons, I love living in Scotland. One of them is the fact that I can pay for 100% renewable electricty for what is now a lower price than most of those who are relying on fossil fuels.

Indeed, Scotland is something of a world leader in its carbon reduction goals. Scotland has the world's most ambitious legally-binding carbon reduction goals (42% from 1990 levels by 2020 - compare Australia's target of a 5% reduction from 2000 levels by 2020). It is also aiming to produce enough renewable electricity to cover 100% of domestic demand by 2020, and is largely on track towards this goal. It is leading the field in research into some promising new varieties of renewable power based on waves and tides.

But the current Scottish Nationalist government also plans to exploit its large (though rapidly declining) North Sea oil and gas reserves, which, when extracted, refined, sold and burned, will add something like 5-10 billion tonnes of CO₂. It will take many decades for the emissions saved by the previously mentioned targets to "pay off" this carbon debt. The value of these reserves is critical to the government's economic case for Scottish independence, yet exploiting them seriously undermines the image of an independent and green Scotland that First Minister Salmon wants to sell.

In the end, if we want a habitable planet that bears any resemblance to the one we currently enjoy, we need to leave the vast majority of fossil hydrocarbons safely underground.

In place of a post on nuclear power

Since even before the disaster at Fukushima, I was planning a lengthy post (or series) considering the place of nuclear power amidst our climate and ecological crises. Towards this post, I now have thousands of words and scores of links (as I do on a number of other topics that are too large for me to find the time to address them with anything like the attention they deserve).

As it seems unlikely that I am going to publish these thoughts anytime in the immediate future (given other deadlines), it seemed like a waste if I did not at least point any thoughtful readers towards this discussion between George Monbiot and Theo Simon. Consisting of a somewhat lengthy email interchange over the last few months now published by George on his website, it is is far and away the best exploration that I have found of the some of the key ethical and political issues behind the nuclear debate, which can get often mired in the technical and economic aspects of the question (as important as they each are).

So consider this discussion a primer for the day when I get around to putting forward my own thoughts in public. For those who may be interested to know where I stand, I will simply say that I am deeply sympathetic to both authors. Now go and read the thread.

Can we destroy creation? Hubris and self-destruction

We can't destroy creation. Alpha Centuri is going to be just fine, climate change or not. We can't even destroy the planet. It's survived meteors, tectonic upheavals and ice ages. It's a pretty durable lump of rock.

Nonetheless, I frequently see people claiming that it is arrogant to think that tiny little humans are having such a large impact of the functioning of planetary-scale systems as is implied by the mainstream science of climate change, ocean acidification, soil degradation, biodiversity loss and so on. Sometimes this objection has a dose of piety injected: God is in charge of the world; we can't damage it (at least, not more than superficially or locally).

But isn't it arrogant (and historically ignorant) to think that our capacity for destruction does not extend to wiping out entire ecosystems? We have done so on colossal scales in recorded history. Vast forests have disappeared in the face of the axe and bulldozer; seemingly endless prairies have all but disappeared under the plough. Haven't we grown to seven billion and rising, spreading into every continent and visibly altering huge tracts of the earth's surface? Why would we be surprised at anthropogenic climate change or ocean acidification or biodiversity decline when we consider our collective effects in a wide range of areas? Aren't our nuclear arsenals capable of obliterating the vast majority of life on earth at a moment's notice? Haven't we fundamentally altered the appearance, behaviour and distribution of species through millennia of domestication and exploration? Haven't we sent thousands of recorded species (and likely tens or hundreds of thousands of unrecorded species) extinct? Haven't we damned and/or diverted the majority of the world's great rivers, and even (almost) dried up what was previously the fourth largest lake in the world? Haven't we flung craft into orbit that can monitor many of these changes in astonishing detail?

If human civilisations (even ones who considered themselves Christian) have risen and fallen in the past, why would we assume that ours will be immortal? And if human actions have contributed to historical collapses, why would we rule out such influence today?

If we have done all this, then if we have also dug up and burned over 300 billion tonnes of fossil hydrocarbons, might not here, as in so many other places, our capacity for altering our surroundings be manifest? If we have changed the chemical composition of the atmosphere and oceans in measurable and statistically significant ways, might not these changes have far-reaching consequences and implications for life (human and otherwise) throughout the atmosphere and oceans? If we can measure the changes in radiation that occur as a result of these alterations, if we can measure shifts in the timing of flowerings, growing seasons, hibernations and migrations, observe massive and alarmingly rapid alterations to the frozen places of the planet, notice systematic and unprecedented shifts in humidity, precipitation, temperatures over land and sea (and in the waters) and rising sea levels - if we can observe these changes occurring and have an excellent theory that accounts for all the data and which has withstood every criticism levelled against it, seen off all competing explanations and gained the acceptance of every single relevant scientific body of national or international standing in the world, then what is to be gained by withholding judgement? And if we have good reason to be deeply concerned about the already manifest and likely future consequences of the observed, modelled and projected trends, if these consequences threaten the habitability of the planet and its ability to provide sufficient food for our societies and habitat for all our fellow creatures, if our neighbours are deeply vulnerable to these changes, if the most vulnerable are also those who have done least to contribute to the problem (the poor, future generations and other species), then might not Christian discipleship embrace humble acceptance of our predicament and an earnest search for responses that express repentance, care and prudence?

Furthermore, if many of the social and personal changes required are not simply consonant with, but already actively required by, Christian discipleship due to the rejection of idolatry, greed and consumerism, if the infrastructural changes are both affordable and viable, if those most vocally opposed to these changes have a history of engaging in less than honest advocacy and have a business practice that currently kills millions of people annually, then might we not have a strong case for prophetic witness in defence of the goodness of the created order, in pursuit of justice for the suffering, in the hope of wise care for our children's future?

There are no merely local famines

In a globalised society, there are no merely local famines, or revolutions, or failed states.

Many of our most severe ecological threats converge on the stability of the global food supply. The most explosive consequences of food shortages are not population decline from starvation, but civil unrest and conflict (as well as increasing vulnerability to disease/pandemic). During the 2008 food price spikes, there were riots in sixteen countries. And the most visible political consequence of the 2010 food price spike was the Arab Spring (though again there were protests and riots in many other countries). Yes, of course there are other underlying factors in every country affected, but the spike in the price of bread was the initial spark in nearly every country that saw significant instances of civil unrest in the Middle East and North Africa (MENA). The protests that ultimately brought down governments in Tunisia, Libya, Egypt (and possibly Syria) all had the price of bread as their trigger (as did those in Bahrain and elsewhere). And why were prices so high in 2010? Again, all kinds of systematic reasons (biofuels taking an increasing share, changing diets, speculation, government hoarding in response to an initial rise), but the short term trigger was almost simultaneous crop losses from extreme weather events in Argentina, Australia, Pakistan and Russia (which famously stopped exporting wheat after its six sigma heatwave). Food price spikes are inconvenient in the west, where we spend less than 15% of our income on food, but disastrous in the many places with otherwise somewhat stable governments where large parts of the population spend more like 75%+ of their income on food.

The consequences of political unrest are not confined to the poor country. To pick one consequence: our taxes here in the UK recently went towards funding war in Libya, despite an austerity programme of slashing government services in response to the worst recession since the Great Depression. Refugee flows from all the various places involved have also increased. Major protests in the US and elsewhere this time last year questioned the direction of the present economic order. These explicitly drew both inspiration and organisational links from elements of the Arab Spring before being brutally suppressed - perhaps not as brutally as in Syria, but if you had your eyes open last autumn there was plenty of state-sponsored violence happening against protesters in free(r) countries, much of which was never acknowledged or addressed by the justice system.

This is not at all to claim that climate change "caused" the Occupy movement in any straightforward way, simply to chase one strand of causal links as an illustration of the global implications of crises in a single region.

Failed states have all kinds of knock-on effects on their neighbours and the rest of the world. Think about the extra costs to global shipping due to Somalian piracy (leading to many shipping companies eagerly awaiting the further opening up of Arctic shipping lanes to avoid the area entirely), about the seedbed of terrorism that Afghanistan has represented since the US turbo-charged the factions against Soviet invasion, about the effect on global oil prices (and hence the global economy) of war in Libya (or Iran...), about the ongoing repercussions of the Arab/Israeli conflict partially driven by the planned failure/sabotage of the Palestinian state. And so on. The global system can handle a few failed states, but since it does so by distributing the costs across the whole system (UK taxpayers paying for wars in Libya), it does so by increasing the stress on the system as a whole. Electricity grids are a good analogy here, actually - grids can handle the sudden failure of a certain number of elements in the grid, but do so at the cost of placing the entire grid at greater risk of collapse. Globalisation is a super-grid for economic and political stability: failure in one part can be accommodated by increasing stress across the board. But only to a point.

This is why Joseph Tainter says in the final chapter of his intriguing and seminal book, The Collapse of Complex Societies that there can be no local collapses in a global system. The term "catabolic collapse" is sometimes used, which refers to a collapse in one part of a system becomes self-reinforcing and ends up taking down the whole show (see here for a much more detailed and insightful discussion of this concept by John Michael Greer).

So when you read about the coming food price spike of late 2012 as the effects of the US drought kick in, don't just think about poor Indians struggling to put food on the table, but also think about the $700b-odd the US spends on its military (over $1t on "national security" as a whole), about the possible break-up of the EU (troubles in Greece are complex, but one of the causes/manifestations/worsening of their crisis is the fact that they receive per capita more refugees and undocumented immigrants fleeing struggling MENA countries than almost anywhere else in the EU and it has seen a big jump in recent years), about deforestation in Indonesia and elsewhere (which is linked, in complex ways, to food prices), and so on.

Global crises require global (as well as local, provincial, national, regional) responses. We can't simply pull up the drawbridge and hope to weather the storm.

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.

Musical interlude: our biggest challenge

For those whose attention span does not extend to the length of the previous video.

Lines of evidence: How do we know about climate change?

For anyone still confused as to how we know that the climate is changing and that the changes are largely driven by human activities, this 26 minute video from the US National Academies gives an excellent and authoritative overview of the evidence. None of this is remotely controversial amongst the world's peak scientific bodies, despite much obfuscation and confusion through the media and blogs for political, economic and ideological purposes.

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.

Australian carbon policy makes coal plants more profitable

"Australia's highest-emitting brown coal electricity generators are between $400 million and $1 billion better off than they would have been if there were no carbon tax, new modelling shows."

- Lenore Taylor and David Wroe, Carbon tax [price] leaves big polluters better off, SMH, 6th September 2012.

Some days, I think Australia's climate policy is a joke: a sick joke to be aiming for a 5% reduction from 2000 levels by 2020 when the UK has legislated targets for a 50% reduction from 1990 levels by 2027, and a sick joke to allow a majority of that target to come from international offsets, and a sick joke to plan on doubling Australian coal exports over the next decade when we are already the largest coal exporter in the world (and our coal exports don't count towards our targets). Australians have the highest per capita carbon footprint in the OECD (even ignoring our coal exports) and yet our targets for emissions reductions are some of the weakest.

This is indeed a major Gillard failure, taking baby steps when we need to be running. It is an even bigger failure of Australian culture, since we collectively choose (and vote for) short term personal acquisitiveness (a.k.a. greed) over justice and prudence (a.k.a. doing our fair share of working for a habitable planet).

Fortunately, the good news of Jesus has a lot to say to those who steal from their neighbours and can't see very far.

And now for the weather report

Perhaps a few more weather reporters giving this kind of context could help public understanding, since studies indicate that weather reporters remain one of the primary sources of information about climate (despite many reporters having little or background in climate themselves).

Very helpfully, the American Meteorological Society has updated its statement on climate change to reflect scientific research completed since the last one in 2007. The new statement is considerably stronger in its language than its previous one. Here are a few tastes of the new statement:

"Warming of the climate system now is unequivocal [...] many of the observed changes noted above are beyond what can be explained by the natural variability of the climate. It is clear from extensive scientific evidence that the dominant cause of the rapid change in climate of the past half century is human-induced increases in the amount of atmospheric greenhouse gases [...] Since long-term measurements began in the 1950s, the atmospheric CO2 concentration has been increasing at a rate much faster than at any time in the last 800,000 years. [...] Climate is potentially predictable for much longer time scales than weather for several reasons. [...] A helpful analogy in this regard is that population averages of human mortality are predictable while life spans of individuals are not. [...] Future warming of the climate is inevitable for many years due to the greenhouse gases already added to the atmosphere and the heat that has been taken up by the oceans. [...] Global efforts to slow greenhouse gas emissions have been unsuccessful so far. However, were future technologies and policies able to achieve a rapid reduction of greenhouse gas emissions — an approach termed “mitigation” — this would greatly lessen future global warming and its impacts. [...] In the 21st century, global sea level also will continue to rise although the rise will not be uniform at all locations. [...] Atmospheric water content will increase globally, consistent with warmer temperatures, and consequently the global hydrological cycle will continue to accelerate. [...] changes in precipitation patterns are expected to differ considerably by region and by season [...] more severe droughts and floods [...] significant regional shifts in precipitation patterns [...] heavy precipitation events will continue to become more intense and frequent [...] longer dry spells between precipitation events in the subtropics and lower-middle latitudes [...] Widespread retreat of mountain glaciers is expected to eventually lead to reduced dry season flows for glacier-fed rivers. Drought is projected to increase over Africa, Europe, and much of the North American continental interior, and particularly the southwest United States. [...] more extreme warm periods and fewer cold periods are expected [...] more severe episodes of extreme heat. Critical thresholds of daily maximum temperature, above which ecosystems and crop systems (e.g., food crops such as rice, corn, and wheat) suffer increasingly severe damage, are likely to be exceeded more frequently. [...] It is unclear if the land biosphere and oceans will be able to continue taking up carbon at their current rate into the future. [...] Another unknown is the amount of methane that will be released due to high-latitude warming. There are indications that large regions of the permafrost in parts of Alaska and other northern polar areas are already thawing, with the potential to release massive amounts of carbon into the atmosphere beyond those being directly added by human activity. The portion of the increased CO2 release that is absorbed by the world ocean is making the ocean more acidic, with negative implications for shell- and skeleton-forming organisms and more generally for ocean ecosystems."

If you're pressed for time, or already familiar with recent climate research, then you can just skip to the conclusion. Here it is in full:

"There is unequivocal evidence that Earth’s lower atmosphere, ocean, and land surface are warming; sea level is rising; and snow cover, mountain glaciers, and Arctic sea ice are shrinking. The dominant cause of the warming since the 1950s is human activities. This scientific finding is based on a large and persuasive body of research. The observed warming will be irreversible for many years into the future, and even larger temperature increases will occur as greenhouse gases continue to accumulate in the atmosphere. Avoiding this future warming will require a large and rapid reduction in global greenhouse gas emissions. The ongoing warming will increase risks and stresses to human societies, economies, ecosystems, and wildlife through the 21st century and beyond, making it imperative that society respond to a changing climate. To inform decisions on adaptation and mitigation, it is critical that we improve our understanding of the global climate system and our ability to project future climate through continued and improved monitoring and research. This is especially true for smaller (seasonal and regional) scales and weather and climate extremes, and for important hydroclimatic variables such as precipitation and water availability.

Technological, economic, and policy choices in the near future will determine the extent of future impacts of climate change. Science-based decisions are seldom made in a context of absolute certainty. National and international policy discussions should include consideration of the best ways to both adapt to and mitigate climate change. Mitigation will reduce the amount of future climate change and the risk of impacts that are potentially large and dangerous. At the same time, some continued climate change is inevitable, and policy responses should include adaptation to climate change. Prudence dictates extreme care in accounting for our relationship with the only planet known to be capable of sustaining human life."

There is much to commend in this new statement. It clearly and unambiguously affirms the three basic pillars of climate science: (a) the planet is warming rapidly; (b) humans are the dominant cause; (c) the consequences are a serious threat. There is not a relevant scientific institution of national or international standing that questions any of those three claims.

At the same time, the new AMS statement acknowledges many areas of lower confidence, where research is ongoing, including: the precise sensitivity of the climate to greenhouse gases; the precise role of clouds and aerosol particles; the precise distribution of disruptions to the hydrological cycle; the ongoing effects of natural variation within the larger trends; the rate of ice sheet disintegration and sea level melt; the potential negative side effects of geo-engineering proposals; and perhaps most importantly the uncertainties in the human systems that cause and are impacted by climate change: how fast will we continue to modify the chemical composition of atmosphere and oceans? And how well will we respond to the risks and threats these changes will bring?

Given the uncertainties, both in the geophysical systems and especially in the human systems that drive and respond to them, the AMS statement remains agnostic about the most important debate regarding the threat of climate change: does climate change represent a level of risk that is merely disastrous or truly catastrophic?

The closest it comes to addressing this question is in the very interesting final sentence: "Prudence dictates extreme care in accounting for our relationship with the only planet known to be capable of sustaining human life." We're not talking merely about losing the polar bears, or an acceleration of species extinctions more generally, or even severe economic disruption or a rising threat of climate-related conflict. Implicitly at least, this statement acknowledges that what is at stake is the ongoing capacity of the planet to sustain human life.

UPDATE: The scriptwriter for the video above shares his thinking behind the clip.