If you read my “Science Headlines” postings in the “Daily News Bucket” diaries regularly, you’ve noticed that I talk a lot about global warming, and most of the news isn’t good. If you’ve been preoccupied with the war, scandals in Washington, getting Democrats elected, and so forth – all necessary, justifiable things – you might have missed how the pieces are all falling together day by day. So here is a summary of the pattern that’s forming, courtesy of Steve Connor at The independent (UK): the story that you won’t hear on the evening news or in the MSM, at least in the US. The bottom line is, based on what we discovered in 2006, our situation looks like it’s more precarious than we thought:
You could be forgiven for thinking that you’ve heard it all before. You may think it’s time to turn the page and read something else. But you’d be wrong. 2006 will be remembered by climatologists as the year in which the potential scale of global warming came into focus. And the problem can be summarized in one word: feedback.
[snip]
Feedbacks can either make things better, or they can make things worse. The trouble is, everywhere scientists looked in 2006, they encountered feedbacks that will make things worse – a lot worse.
Previous warnings by the UN’s Intergovernmental Panel on Climate Change (IPCC) – most recently in 2001 – said little about feedback effects, because so little was known at the time. Climate change was expected to happen slowly and gradually, giving governments and economies time to react. The growing consensus among climate scientists is that this isn’t how the world works:
They fear that feedback reactions may begin to kick in and suddenly tip the climate beyond a critical threshold from which it cannot easily recover.
Climate feedbacks could turn the Earth into a very different planet over a dramatically short period of time. It has happened in the past, scientists say, and it could easily happen in the future given the unprecedented scale of the environmental changes caused by man.
Feedsbacks can be positive – reinforcing warming – or negative – acting as a “brake” on climate change.
“The main concern is that the more we look, the more positive feedbacks we find,” says Olivier Boucher, a climate scientist at the Met Office. “That’s not the case when it comes to negative feedbacks. There seems to be far fewer of them.” The sentiment is echoed by Chris Rapley, the director of the British Antarctic Survey in Cambridge: “When we look at the list of all the feedbacks in the climate, the list of positive feedbacks is worryingly long – a lot longer than the negative feedbacks. To be honest, it’s a wonder that the climate has remained so stable.”
You often hear the estimate (by Al Gore, for example) that we have “10 years” before we reach the “tipping point,” the point of no return where, like flipping a switch, we knock the climate into a different stable pattern that will be very difficult to change back to our “old climate.” However, for Arctic sea ice, the tipping point may be today:
In March [2006], NASA satellites monitored a 28-year record low for winter sea ice. Normally sea ice recovers during the long Arctic winter, but this was the second consecutive year that the ice failed to re-form fully to its previous winter extent.
This meant there was less ice at the start of the northern summer, with the result that last September saw the second monthly minimum for summer sea ice – almost hitting the record minimum set in September 2005.
During the past four or five years, there has been an acceleration in the rate at which sea ice is melting, a change that some scientists put down to a positive feedback. “Our hypothesis is that we’ve reached the tipping point,” [emphasis added] says Ron Lindsay of the University of Washington in Seattle. “For sea ice, the positive feedback is that increased summer melt means decreased winter growth and then even more melting the next summer, and so on.”
You begin to see why the tone from climate specialists has gotten more shrill in 2006. Unfortunately, Arctic sea ice (whose disappearance will lead to the extinction of the polar bear) isn’t the only case of positive feedback at work in the arctic:
…the frozen permafrost of Siberia and northern Canada, …lock up vast stores of carbon in the form of methane, a gas formed by the decomposition of organic matter. For more than 12,000 years, this methane – a greenhouse gas 20 times more potent than carbon dioxide – has been safely stored under the permanently frozen ground. But now the permafrost is melting and the gas is bubbling free into the atmosphere.
Sergei Kirpotin, a botanist at Tomsk State University in Russia, has been studying the extent of the melting permafrost of Western Siberia, the site of the world’s biggest frozen peat bog. During the past few years, he has watched lakes getting bigger and bigger as the solid permafrost underneath liquifies.
Normally, patches of white lichen on high Siberian ground reflect the sun’s rays and help to keep the ground underneath cold. But as the dark lakes expand, more heat is absorbed and more permafrost melts. “As we predicted in the early 1990s, there’s a critical barrier,” says Professor Kirpotin. “Once global warming pushes the melting process past that line, it begins to perpetuate itself.”
The once-frozen peat bogs of Siberia – bigger than France and Germany combined – began to “boil” furiously in the summer of 2006 as methane bubbled to the surface. [emphasis added (as if I needed to!)] Exactly how much is being released into the atmosphere is unknown, although some estimates put it as high as 100,000 tons a day – which means a warming effect greater than America’s man-made emissions of carbon dioxide.
But Katey Walter of the University of Alaska believes even this could be seriously underestimated. In a study published in Nature in September, Walter and her colleagues calculated that the level of methane emissions from Siberia could be anywhere between 10 per cent and 63 per cent higher than anyone had hitherto suspected. “We have shown that the North Siberian lakes are a significantly larger source of atmospheric methane than previously recognized,” she says.
Let that last sentence sink in again. “We have shown that the North Siberian lakes are a significantly larger source of atmospheric methane than previously recognized.” Perhaps society’s inaction to date is at least partly because scientists are trained to speak cautiously, to couch their conclusions with words like “probably” that give politicians and businessmen an excuse for inaction.
How strange to consider that the entire fate of the planetary ecosystem, the lives of billions, the extinction of species, might rest on the social habits ingrained in scientists during their training… (“might rest” – see, I do it too, instinctively. It’s the way we’re trained to speak, as much a part of our fabric as Scarlet O’Hara’s Southern drawl. Y’all need to listen past our communicative limitations to see what we’re tryin’ to say here, please!)
But I digress.
The Earth has been a very accommodating planet. During the past 200 years, it has absorbed more than half of all man-made emissions of carbon dioxide through natural carbon “sinks”, mostly in the ocean but also on land. The rest of the emissions have been left in the air to aggravate the Earth’s natural greenhouse effect, so raising global average temperatures.
But what if something were to interfere with these very useful carbon “sinks”? Can we forever rely on them to remain sinks, or could they turn into dangerous sources of atmospheric carbon? A huge international team of climatologists asked these questions in a little-known study published in the July issue of the Journal of Climate. The conclusion makes depressing reading… …Many models suggest that the terrestrial biosphere could become a net carbon producer by the mid 21st century. Signs are that it is already happening in some parts of the world.
· As the planet heats up, decay in the soil increases, releasing more carbon dioxide to the atmosphere.
· As carbon dioxide is absorbed by the oceans, its pH drops (the water becomes less alkaline), making it harder for microscopic organisms to form their calcium carbonate shells… Shells that fall to the ocean floor when the animal dies, removing the CO2 (in the form of carbonate) from circulation with the atmosphere.
· As the oceans heat up, overall circulation is expected to drop as the “pump” in the north Atlantic that drives the Gulf Stream and much of the rest of global oceanic circulation slows (it already is slowing). This leads to decreased nutrients rising to the ocean surface to fertilize plankton that remove CO2 from the air. And it may result in increased wildfires (see today’s “Science Headlines”) in the Western US, removing another source of CO2 removal.
· A warming ocean might “belch” methane currently stored on the ocean floor in the form of clathrates – an icy compound holding the methane trapped. Heat the ice too far and it decomposes, releasing the methane, and knocking up the global thermostat further.
There are negative feedbacks, of course, otherwise the planet would never have cooled off after the age of the dinosaurs. Here are a few; unfortunately, they tend to work slowly:
· The deeper oceans resulting from melting polar ice would apply additional pressure to the methane clathrates on the sea floor, acting to stabilize them. We do not know which effect will win out over time, however.
· Newly exposed mountaintops where snow has melted will erode over time, removing carbon dioxide from the atmosphere.
· IF (and it’s a big if) there are enough water and nutrients available, plants can remove some extra carbon dioxide from the air. This was a rallying point for climate change deniers for years, but in practice it looks like it’s not likely to be the carbon sink they hope for in the time scale we need.
· If it wasn’t for human activity, we’d likely be heading into an ice age, over the next few millenia…
I could go into greater detail and dig up more examples, but I suspect the next IPCC report, due in 2007, will do so better than I could.
*******************
This is the point where I’m supposed to tell you all to run out and buy compact fluorescent bulbs and hybrid cars and recycled everything and locally grown produce and have your city run on wind and solar power and if we’re all virtuous enough, it will all be OK. And maybe it will. But 2006 was the year where, as one who spends part of each day scrying the signs, I can honestly say I just don’t know anymore.
I could offer you the psychology of fundamentalist millennialism dressed up in a scientific wardrobe, and tell you our salvation will come from the discovery of affordable fusion power at CERN, and maybe it will. But faith and hope are not the shtick I’m trained to offer, nor is it my nature to do so. I’ll leave that decision to each person’s conscience. (Although I will say that, in the darkest years of Reagan’s nuclear saber rattling, Mrs. K.P. and I literally decided to have our first child as “a declaration of hope.” …And the second, of course, as a playmate for the first. Funny how your perspective changes after the first one, LOL.)
So where does that leave me? I guess in the same place as a person facing an uncertain medical prognosis, savoring each encounter with nature and others that much more sweetly. If Gaia’s experiment with self-consciousness and rational thought should turn out badly, it does not change the fact that we are the eyes and ears of the universe (at least in this little corner of the universe) reflecting back on itself. And as the bearers of such a gift, such a burden, we have a moral obligation to experience each moment to the fullest. A gift, a responsibility, we have in any case, regardless of global warming.