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.

Not with a bang but with a sustained leak

Real Climate: Why Arctic methane release is bad, not catastrophic. This is a very important post. Many have been deeply worried about the possibility of a so-called "methane gun" in which truly staggering volumes of frozen methane clathrates that sit on and under the ocean floor of the Siberian continental shelf are released in a runaway feedback as the Arctic Ocean warms. Since methane (CH₄) has something like 100 times the warming potential of carbon dioxide over a twenty year period, it has been hypothesized that a rapid release of large volumes of stored methane could cause a sudden and likely catastrophic surge in global temperatures. A variation or accompaniment to this scenario is the rapid release of methane from thawing permafrost in Siberia. In the linked post, a senior climatologist argues that it is far more likely that methane release will be chronic rather than acute, and given methane's relatively short atmospheric residency (about ten years), this will lead to a dangerous (though not immediately catastrophic) rise then stabilisation of methane levels, supplementing but not overwhelming warming from carbon dioxide. However, since atmospheric methane gradually degrades to carbon dioxide in the presence of oxygen, a slow release would not only give a bump to methane levels but would also see carbon dioxide levels continue to rise. Unlike methane, carbon dioxide is basically forever, with about half of any increase in atmospheric concentration we experience likely to remain for centuries and about a quarter likely to remain for at least ten thousand years. So a relief (of sorts) for us. It's a bit like finding that the Nazis don't, as feared, have a nuclear weapon, but they do have twice as many conventional forces as was thought.

CD: A recent NASA study suggests that climate change may modify 40% the earth's surface from one biome (e.g. forest, savanna, tundra, etc.) to another.

ABC Religion and Ethics: The New Evangelicals: How Christians are rethinking Abortion and Gay marriage. Despite being published by the ABC, this piece (an extract from a new book) has its eyes on the US scene. How applicable are the trends it identifies elsewhere amongst evangelicals?

Guardian: More farmers needed. Feeding seven, eight, nine, ten billion without strip-mining the soil, using the atmosphere as a carbon dump, squeezing out biodiversity, depleting finite fuels or overloading rivers, lakes and oceans with nutrients requires more organic poly-cultural farming, which can often be more productive per unit of land overall than present industrial monocultural farming. However, it is less productive per unit of labour, meaning more people employed (again) in growing food, which probably means higher food prices and a greater share of incomes devoted to food. This in turn may help address obesity, though at the risk of increasing malnutrition associated with poverty. Hence, addressing inequality is also critical.

Peter preaches on the parable of the talents (Matthew 25.14-30). This passage is often used as a key plank in a justification of usury. There are elements in the narrative and context that suggest a very different reading. Peter highlights the key theological question lying behind this hermeneutical issue: which kind of God do we serve?

McKibben: On being hopefully naïve about getting corporate money out of US politics and why being cynical is hopeless.

Guardian: What have trees ever done for us?

NYT: My Guantánamo Nightmare. There are good reasons due process has come to be highly cherished in all civil societies.

Monbiot: The limits of vegetarianism, in which George changes his mind and shifts to ethical semi-vegetarianism. The Conversation publishes an even more provocative piece against ecological vegetarianism, and a very interesting discussion in the comments ensues.

SMH: Energy and water. In the 20thC, global energy use increased thirteen-fold and water use increased nine-fold. The two are related and any future has to consider our water habits, which might be less about having short showers than having cold ones, since energy production is one of the most water-intensive things we do (though conversely, where water is scarce, desalination is one of the most energy-intensive things we do).

On thin ice

Guess the graph competition answer
Last Wednesday, I posted this graph and asked for guesses as to what it represented. Aside from a few humorous suggestions, most answers were in the right ballpark, suggesting it had something to do with our melting cryosphere. This is perhaps one of the best known effects of climate change (or that part of climate change known as global warming), yet there is widespread confusion about the details.

The correct answer is that the graph represents the Arctic sea ice volume over the last few decades. The worrying downward trend is accelerating, but, unlike the graphs for Greenland or Antarctica, which are also heading down, the number on the y-axis are absolute figures. That is, while Greenland and Antarctica are losing increasing amounts of ice, compared with their total volumes, the amounts currently being lost are miniscule. For them to completely melt would be catastrophic, raising sea level tens of metres, but this is likely to take centuries, if not longer. However, the Arctic Ocean is getting seriously close to "ice-free" in summer,* an event most of us are likely to see within our lifetimes, and which we may well witness this or next decade, according to some experts. Certainly, extrapolating those trend lines points to an early grave for our planet's white top. The lines are unlikely to simply follow that curve, for various reasons, but scientists can identify no reasons to think the trend will reverse anytime soon.
*As long as Greenland still has significant amounts of ice, a residual amount of sea ice is likely to survive. "Ice-free" is usually qualified as largely ice-free. This is different again to an ice-free North Pole, which simply means that there is no sea ice cover at the North Pole, while there might still be some polar ice cap remaining.

What is Arctic sea ice?
It is important to highlight that we are talking about sea ice, that is ice that floats on top of the Arctic Ocean and which expands in winter and contracts in summer. It is generally not nearly as thick as people imagine (averaging just a metre or two) and any given piece of ice is unlikely to be more than a few years old, since it is constantly in motion due to wind and ocean currents and each summer much of it melts. Nonetheless, there has been permanent sea ice cover on the Arctic Ocean for at least somewhere between the last 700,000 and 4 million years, allowing the evolution of unique and endemic species (i.e. not found elsewhere). Since the ice is floating, the concern is not that melting will directly raise sea levels, both because the actual volume of ice is pretty miniscule compared with Greenland and (especially) Antarctica (for comparison, while Arctic sea ice is generally at most a few metres thick, Greenland's ice sheet is generally more than 2 km thick, and over 3 km at points. Antarctica is about ten times greater in volume again) and because floating ice displaces an almost identical volume of water to that contained in the ice (melting ice in a glass of water doesn't cause it to overflow).

Why are people worried?
Concern about the loss of Arctic sea ice is eightfold.

First, it is a canary in the goldmine: a visually dramatic sign of temperature changes that is relatively easy for the public to grasp.

Second, it threatens the unique and endemic Arctic biota (of which polar bears are of course the poster child).

Third, this in turn undermines the way of life of various indigenous groups in the Arctic, who rely on hunting and on the existence of sea ice for their livelihood.

Fourth, less floating white ice means more exposed dark water, which absorbs more solar radiation, increasing the total heat budget of the planet, and specifically of the Arctic Ocean.

Fifth, a warming Arctic Ocean and atmosphere speeds the melt of permafrost in Canada, Siberia and Alaska, not only threatening infrastructure built on it, but also releasing stored methane, a highly potent greenhouse gas that degrades into carbon dioxide, making it both a short term climate nasty and a long term headache.

Sixth, and perhaps of even greater concern, warmer waters increase the rate at which vast submarine deposits of methane clathrates destabilise and are released to the atmosphere, giving a further kick to warming. There is some debate about whether this process is likely to be slow and gradual or whether it might occur relatively suddenly, a process somethings colloquially called a "clathrate gun".

Seventh, the warmer the Arctic Ocean gets, the warmer Greenland is likely to get, and the faster its glaciers slide and melt into the sea. 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. Altogether, there is enough frozen water in Greenland to raise global sea levels by more than seven metres.

Eighth, 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 (see video below).

Area vs volume
Another crucial distinction to keep in mind (apart from the difference between wafer-thin and highly vulnerable floating sea ice and gigantic land-based ice sheets that are both more stable and yet ultimately of greater direct threat) is between sea ice area/extent on the one hand and volume on the other. Area/extent is the easiest metric to measure with a satellite image (there is a slight technical difference between these two terms, but they are both basically concerned with a two dimensional account of how much of the Arctic ocean is covered with floating sea ice). Extent has been dropping at a slower rate than volume, which means that the remaining ice is getting thinner. Those only looking at the numbers for area or extent might be fooled into thinking the decline is only worrying, rather than alarming. While summer minimum extent has dropped by about a third over the last thirty years, volume is down by more than three quarters. And human activities are largely to blame.

The road ahead
The Arctic is one of the places where the climate change is already hitting the road. The transformation of the landscape is not merely a computer projection, but observable today. Its consequences are already negative, but the trajectory is even worse. What kind of path are we walking? And where will we find the courage and humility to turn around if we don't like where it is going?
The video at the top of the post is from a recently broadcast BBC programme, covering some of the implications of this story, which also appeared on the BBC news site.

No way out? Peak oil will not save us from climate change

You may not be able to take it with you, but you can take it down with you. Remember, George Monbiot is sometimes regarded as one of the more optimistic voices on ecological issues.

"The problem we face is not that we have too little fossil fuel, but too much. As oil declines, economies will switch to tar sands, shale gas and coal; as accessible coal declines, they'll switch to ultra-deep reserves (using underground gasification to exploit them) and methane clathrates. The same probably applies to almost all minerals: we will find them, but exploiting them will mean trashing an ever greater proportion of the world's surface. We have enough non-renewable resources of all kinds to complete our wreckage of renewable resources: forests, soil, fish, freshwater, benign weather. Collapse will come one day, but not before we have pulled everything down with us.

"And even if there were an immediate economic cataclysm, it's not clear that the result would be a decline in our capacity for destruction. In east Africa, for example, I've seen how, when supplies of paraffin or kerosene are disrupted, people don't give up cooking; they cut down more trees. History shows us that wherever large-scale collapse has occurred, psychopaths take over. This is hardly conducive to the rational use of natural assets.

"All of us in the environment movement, in other words – whether we propose accommodation, radical downsizing or collapse – are lost. None of us yet has a convincing account of how humanity can get out of this mess. None of our chosen solutions break the atomising, planet-wrecking project."

- George Monbiot, "Let's face it:
none of our environmental fixes break the planet-wrecking project".

While discussing such matters with my supervisor a few months ago, he wryly observed, "You know you are in trouble when you say, 'Only the Black Death can save us now'".

Monbiot points out in the full article that Fatih Birol, the chief economist of the International Energy Agency, admits that peak oil passed in 2006. Yet this hasn't lead to economic collapse (yet) because the shortfall in liquid conventional oil has so far been filled by tar sands and liquid methane. The pursuit of such resources to avoid a shortage of oil is taking us directly into the vast carbon reserves of non-conventional and alternative fuels, illustrating the Scylla and Charybdis of peak oil and climate change. Some commentators have expressed the hope that peak oil may save us from climate change by limiting the amount of carbon available to be burned. Unfortunately, there is plenty for us to ensure the long term destruction of the only climate under which human society has thrived.

Where peak oil meets climate change

Unconventional fossil fuels are the great unknown area of overlap between the irresistible force of energy security and the immovable object of climate disruption. If we don't leave the vast majority of the tar sands, oil shale and methane clathrates buried, then we can pretty much kiss any chance of a stable and livable climate for the next few decades, centuries and millennia goodbye. If we don't exploit them as fast as we can, then we're likely find the global economy increasingly squeezed by significant shortages in liquid fuels within the next decade.

It is of course massively oversimplified, but which would we prefer: driving into the side of a cliff, or falling off the edge of one?
NB My analogy with a car crash is intended to signify that these issues are not merely inconveniences, but will likely affect many aspects of the lives of many people on the planet. Not every car crash is fatal, of course, so I'm not saying that we're "doomed". Indeed, that was the point of originally reaching for this analogy. There is a big difference between the necessity of facing the issues (and the likelihood of some significant losses) and the impossibility of doing anything worthwhile.