In reading postings in one of my favorite blogs recently (Neven’s superlative Arctic Sea Ice blog), it occurred to me that I hadn’t tried to summarize in my mind the two major surprises that scientists recognized in climate change last year. What follows is my take on these surprises:
- Arctic methane is venting much faster than expected; and
- The weather effects of global warming are stronger than expected.
What are the implications? Let’s take them one at a time.
Arctic Sea Ice and Methane
It still amazes me that most people did not see the likelihood that Arctic sea ice was going to take a nosedive to near zero in the 2013-2016 period, because I only had to apply some basic math when I first took a look in 2009: exponential and normal curves.
Until recently, there was only one serious attempt to assess the volume of Arctic sea ice: Maslowski’s PIOMAS model. As I understand it, people tended to dismiss the model because Maslowski said: this is the way I model Arctic sea ice dynamics, and therefore the sea ice volume should change over time in this and this way; and because he asserted without proof in his model that Arctic Ocean water temperature changes had a major role in increased melting over time. However, when I saw that this model was constantly reality-tested by on-the-site sampling, even though each sample was of a small part of the overall Arctic Ocean, I realized that the long-term trends there were likely to be true. And what Maslowski’s model showed, at any time of the year, was an exponentially decreasing Arctic sea ice volume.
By the way, recent Cryosat observations have definitively shown that, if anything, Maslowski’s model has underestimated the rate of volume decrease.
So why, I asked myself, do I not see corresponding decreases in Arctic sea ice area and extent? As I looked at the dynamics of Arctic sea ice, I realized that that could only happen if there was a uniform distribution of Arctic sea ice thickness from, say, zero to twice the average thickness (at any time of year). But what was really going on was that a certain percentage of the sea ice survived between years to become second year ice, third, and so on; but cue to currents, the average age of Arctic sea ice back in 1980 was five years – sooner or later, ice frozen at one end of the Arctic would reach the other end and head south into warmer waters, there to inevitably unfreeze. Instead, thickness (with a little adjustment for the age of the ice) had much more of a normal distribution around the average. And that, in turn, meant that accelerated volume losses at, say, minimum would only show up in area and extent when we reached the fat part of the curve – which, it is now apparent, occurred in 2012.
By the way, the same logic also says that volume and the rest will not go to zero somewhere around 2014 – 2015; we will have reached the other thin end of the distribution, and the exponential decrease in volume will flatten out, exponentially. That’s why I fully expect to see around 1-5% of the ice remaining at minimum until sometime around 2016-2020.
So, as I’ve said, I expected that Arctic sea ice would begin to obviously disappear around now, and I expected the climate change implications of this – including the fact that Russian-Arctic-Continental-shelf methane “clathrates” would begin to release their methane. What I (and apparently others) did not expect was the scale of that release. A Russian sampling of methane bubbling to the surface found huge pockets of the stuff – hundreds of times more than research had suggested might be the case.
Before I go on to discuss this, let me cycle back to the (expected) implications of Arctic sea ice melt. Today’s models simply do not include melt to near zero at minimum in the 2013-16 time period, and a likely follow-on melt to near zero at all times of the year between 2035 and 2045. This in turn, will not directly lead to more carbon emissions. What it will do is decrease Arctic Ocean albedo (from off-white-reflection to dark-blue-absorption of heat from the sun during the spring-summer-fall), and therefore warm up the Arctic Ocean portion of global and ocean temperature. This already is 15-20 degrees Fahrenheit above normal during the summer; we are talking another 25-35 degrees by 2045, taking it to 20-25 degrees during the winter.
The increased water and air temperature should therefore (a) accelerate methane clathrate melt, including that of the deeper waters nearer the North Pole, and (b) both cool and warm winter temperatures of more temperate zones – with the “warm” predominating over time. How can (b) be? Well, warmer Arctic air has more energy, and therefore pushes south against the “jet stream” more strongly, creating weather in which unusually cold Arctic air reaches further south periodically. However, that same Arctic air is steadily warming over time, to the point where by 2050 it should be as warm as or warmer than southern winter air was in, say, 1980.
Implications of the Methane Surprise
Part of the problem with assessing methane’s implications is that most if not all scientists have not factored in 2015-2045 Arctic sea ice melt’s implications for temperatures just a bit further south. Because methane clathrate melt should be understood as part of a “double whammy” for methane – Arctic methane melt at the same time as permafrost melt.
Since (up to a point) methane has a very short half-life in the atmosphere (say, 8-10 years), you need a much greater rate of methane release into the atmosphere than carbon (all right, methane includes carbon too, but methane has a much greater effect on global warming per ppm than carbon dioxide) to achieve a comparable warming effect over time. And yet, studies of 55 million years ago, when the rate of warming was much less, indicates that methane had a major role in causing what Joe Romm at www.climateprogress.com calls “Hell and High Water”, with 90% of species wiped out.
Scientists have made a persuasive case for the idea that, even if methane clathrates are starting to melt and permafrost at the same time (i.e., even if we factor in Arctic sea ice melt), methane emissions will not reach a “danger point” where their effects in the atmosphere will rival that of carbon emissions any time soon – and therefore will avoid the main danger time of carbon emissions, before the lack of fossil-fuel reserves begins to decrease those emissions on its own). The problem is that the Russian observations indicate that those reassurances are based on assumptions about the rate of methane clathrate “bubble” occurrence that far underestimate their rate and/or amount.
So what, then, are the likely implications of this methane surprise? As far as I can see, there are no “likely” implications, because the range of possible methane “bubble” rates, and therefore emission rates, over the next 40 years is so wide. Nor is it clear to me, given that these emissions are occurring in such a localized northern area, just how wide an effect on global warming there will be. However, my best guess is that over the next 40 years there will be a significant, localized effect: Methane emissions will increase Russian and lower-Arctic-sea heat retention over what it would have been by perhaps 25%, with a corresponding increase in Arctic average temperature and Russian permafrost methane/carbon release. This, in turn, may add perhaps ½ degree Celsius to global warming over the next 40 years – and, of course, will add a comparable amount over the 50 years following, at least – always remembering that a major fraction of methane released turns into carbon dioxide, and hangs around in the atmosphere for a hundred years or so on average. In other words, the major effect of the surprise may be a more long-term one: arrival of a ½ - 1 degree Celsius additional increase in “thousand-year” global warming now rather than later, when it would have less practical effect.
The Weather Effect Surprise and Implications
Taking my cue from James Hansen and Joe Romm, I had guesstimated in 2009 that we in the US would first see constant, undeniable reminders that global warming is real in the 2020-2025 timeframe. These reminders would include not only “hundred-year” hurricane-type wind speeds and scorching summers that created Dust-Bowl conditions in many areas, but also an overall burden of disasters that reached 0.1% of GDP even for a country like the US. I believe it was Heidi Cullen that imagined NYC missing a massive hurricane in 2017 and getting one in 2041, by which time the city was prepared and the sewers did not back up and overflow, causing hundreds of thousands of deaths from disease.
But, as Joe Romm noted in his blog, the things that should have been expected in 2020-2025 seem to be happening in 2011-2012, ranging from devastating Australian rainstorms to stupendous Russian wildfires to Hurricane Sandy and its 13-foot storm surge (still short of the 20-odd-foot storm surge that might cause the sewer outlets to be closed and the sewers to back up, but enough to flood the subways and make downtown Manhattan, Queens, and Staten Island disaster areas). It appears that the monetary effects of disasters globally, according to insurers like Munich Re, are 10 times what they were a decade ago, and there is no reason why they should not continue to double or triple by 10 years from now – meaning that the timetable for effects on global GDP should perhaps be moved up by 3-5 years.
The surprise is not that global warming is happening faster than predicted – globally, 2012 was actually about average for the last decade, which in turn means that it was one of the “dips” in our steady, accelerating global temperature ascent. The surprise is that the effects on weather were larger than expected. What I suspect is that forecasts simply assumed that certain catastrophic events would happen more frequently than expected, but could not predict that these catastrophes would spread to areas where they had not before (devastating tornadoes in western Massachusetts), areas that were less adapted to a new set of weather patterns. We are reaching the point where we have not only extremes of existing weather patterns, but also new climates that produce new weather patterns.
And so, I also suspect that the effects of the “weather is changing faster than we expect” surprise are, like the methane surprise, bad but unpredictable. I anticipate that the Nino/Nina cycle and North Atlantic Oscillation patterns that have driven weather around here since time immemorial (i.e., the last 5,000 years) are changing, but will manifest first in longer versions of the extremes of this cycle – and that’s a total guess. Certainly, an extended Nino would mean even greater Dust Bowl conditions and summer heat over a great extent of the US for longer than ever before, even leaving out the effects of the ongoing global temperature warming. Initial predictions show the US except the Northeast and Pennsylvania in catastrophic drought conditions in 2050 – is it possible it could happen before then?
Boy, I hope not. But, as a clueless Presidential candidate noted in 2008, hope is not a plan.
Overall, oddly enough, the implications of these surprises for me are not great. I concluded in 2009 that we desperately needed to cut carbon emissions in absolute terms by 40% 2010-2020, and another 40% 2020-2030. Since then, with extremely minor exceptions, all major countries in the world have utterly wasted their time in that regard. In fact, my definition of functional insanity is to see oil companies and countries seeing Arctic sea ice melt as an opportunity for increased drilling of fossil-fuel carbon pollutants, and the United States seeing a Keystone XL pipeline that solidifies tar-sand drilling that sharply increases the likelihood of the end of all life on Earth as an opportunity worth considering, much less actually being relatively close to implementing it.
So, to my eyes, the horrible effects of the two 2012 surprises simply speed up what’s coming and increase its bad effects in relatively minor ways, and that will be worth it if people wake up now and start doing something globally effective. Except that there’s little sign as yet that people and their leaders are even beginning to understand the urgency of an adequate scale of action.
I wonder what new surprises 2013 will bring? I could really use some good news.