How Fast is Global Warming Happening?

When I began writing _A Nation of Farmers_ last year, one of the first sections I completed was the introduction to the agricultural impact of climate change. I finished it in early March, and felt that I'd produced a fairly cutting-edge synthesis of the implications of Global Warming for food and agriculture - and about the power of food and agriculture to mediate global warming. Pleased that I'd written something useful and that at least one chapter of the book was finished, I sent it off to my publisher for their perusal and turned to other things. I could have just saved myself time and shoved it in the recycling bin, deleted it from my hard drive and taken a nap.

It wasn't that wasn't carefully researched or written, just that the data on climate change is coming in so fast right now that what I wrote this spring is now largely outdated. There are now further refinements, subsequent studies and new models to deal with. I subscribe to a number of news feeds, and people send me additional studies and items of interest. My husband, an astrophysicist who teaches environmental physics also tracks the same material. And what, overwhelmingly I'm seeing, and most scientists seem to be seeing, is that global warming is progressing far faster than anyone would ever have expected.

For example, as recently as this spring, the IPCC report was estimating that arctic ice might disappear in the summers as early as 2050, but more likely towards the very end of this century. Research by James Hansen and other scientists at NASA projected an ice free arctic as early as 2023 this year, which stunned the scientific community. http://news.bbc.co.uk/2/hi/science/nature/7006640.stm In fact, however, this summer's ice retreat was so dramatic, that in, fact, the University of Colorado's National Snow and Ice Data Center is now suggesting that the arctic could be ice free as early as 2015, 8 years from now. In less than six months, we've jumped our predictions for a major tipping point factor up by a minimum of 30 years. That's astonishing - and terrifying.

The IPCC's assessment of when major climate induced famines may occur originally focused on 2050, but yesterday the IPCC released a study suggesting that all agricultural production in Africa may halve in 12 years. http://www.irinnews.org/Report.aspx?ReportId=74481. Given that Africa presently has millions of people struggling to feed themselves, we can only imagine how horrifying this may be. Or rather, we don't have to imagine it - almost all of us will live to watch it. India, set to become the world's most populous country, also stands to lose up to 40% of its agricultural production by mid-century.

A 1 meter sea-level rise http://www.terradaily.com/2007/070925082357.ukuaaqza., may submerge 1/3 of the nation of Bangladesh. According to James Hansen's most recent studies at NASA, an ice-free arctic would virtually ensure we pass the critical 2 degree mark, setting in motion a sea level rise of up to 25 meters. A 1 meter rise could happen as early as 2019, 11 years from now, if sea level rises continue as predicted. Such a rise, incidentally, would do irreparable harm to American, Canadian, Australian and European coastal communities as well.

The IPCC report does not include the impact of tipping points on global warming for the most part - that is, it assumes that effects will proceed linearly, in a convenient, orderly fashion, rather than in the irregular way that nature usually does things. We have ample observational evidence, however, that things like ice melting don't actually proceed linearly, but create feedback loops that accellerate the process. Thus, virtually every scientist whose work I have read, whose studies I've seen, or who I see interviewed makes exactly the same point - everything about climate change is happening much, much, much faster than anyone expected.

I'm married to a scientist, and generally speaking, scientists are carefully trained to equivocate - to say what they don't know, and what the limitations on their knowledge are, to speak in terms of possibilities, rather than absolute truth. One of the most disturbing things about listening to scientists studying climate change, then, is the fear in the voices and words of people not accustomed to be fearful, and the sense that generally speaking, scientists are far more worried than most of us are. We can either believe they are worried because they are foolish, easily frightened and scaremongering, or we can believe they are afraid because they are seeing things they have never seen before with implications that are terrifying, and do not understand why the rest of us are so unafraid.

12,800 years ago, the Younger Dryas climate change occurred. It was the last great climactic shift of the great ice age, and is notable mostly because of its tremendous rapidity - in less 20 years, the world went from warm to cold, entering a 1300 year old ice age. In Maine, over a decade, average temperatures dropped by 28 degrees. But believe it or not, that's not the disturbing bit of data. As Richard Alley, of Penn State University documents in his studies of Greenland ice cores, when the Younger Dryas ended, it did so even faster, within a decade. Fred Pearce quotes Alley as saying, "Most of that change looks like it happened in a single year. It could have been less, perhaps even a single season."

The cause of these radical changes seem to have been all the bad guys of present climate change - melting ice, the ocean conveyor belt, releases from soil and water of stored methane and carbon - that is, the planet changed its entire climate in a matter of decades, or less than a decade or a season because of all the things we're watching right now. And it looks like the first of the great potential tipping points is coming not in 50 years or 40, not when those of us writing now are dead or old and grey and our children grown with children of their own, but very soon, in the next years and decades.

The simple fact is that one of the things we do know is that climate change can happen with astonishing rapidity, and produce radical changes in planetary climate quite quickly. As we gain more and more evidence, one of the things that seems overwhelmingly true is that very little about this is smooth or linear.

Now insert humanity into this. Never before have we had the power to make such a huge change. For example, we could figure in the issue of global dimming alone. Earlier in this post I pointed out that Global Warming is being blamed for a 50% reduction in agricultural production in Africa, especially the Sahel, the subsaharan area many of us in the West associate so strongly with drought and famine. Atmospheric physicist Leon Rotstayn argues that in fact, the drought of the 1980s in the Sahel that led to the Ethiopian famine was probably due less to global warming than global dimming. Neither the IPCC report on climate nor their report on famine in Africa takes full account of global dimming.

Global dimming is an observed phenomenon about which there is comparatively little scientific controversy. It simply points out that atmospheric pollution caused by industrialization has reduced the amount of sunlight we're receiving. And because sunlight striking water is the largest factor in evaporation rates, we are seeing reduced rates of evaporation. This evaporation fuels the monsoons that run across Africa and Asia providing much of the rainy season warming. Dr. Rotstayn argues that our pollution has damaged evaporation rates so much that the Sahel experienced drought and famine. The same, we are warned, could potentially occur in Asia, where billions of people depend on the monsoons for irrigation. http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_prog_summary.shtml

But here's the thing. We know that atmospheric pollutions means that we are getting less sun than we would be without it. We must reduce atmospheric pollution of all kinds, lest we plunge up to 3 billion people into famine and drought, not to mention that millions of deaths from asthma, lung cancer and pollution related health consequences - up to 3 million people annually in China alone. But we also know that in the past, the amount of atmospheric carbon we have at present led to warming of up to six degrees. Right now, it has warmed the planet only 0.6 degrees. One of the most likely explanations for this is that we're simply getting less sun, that a dimming planet has held back global warming. But if we stop polluting, if we do the things necessary to stop global warming, we are likely to reduce our atmospheric pollution as well, leading to a much more dramatic, sudden rise in temperatures.

The arctic sea ice and global dimming aren't the only factors that could accellerate climate change. But they are two of the most urgent and immanent threats to us. None of this research takes peak oil into account. As we refine our understanding of the real and material limits of fossil fuels, trace metals and other resources, it becomes less and less likely that any long term solution involving a mass build-out of renewable energies is likely to occur. That is, we're likely to find our solutions to global warming dramatically restricted by the availablility of energy and wealth. No one, with the exception of Richard Heinberg, has so far full grasped how short a time we have to remediate global warming - perhaps only a matter of a few years in which we are rich enough to begin the conversion of our infrastructure.

And, of course, the reality is that we all talk about 2 degrees and 440 or 450 or 480 ppm as though they are absolute limits, and we'll all be just fine until we hit them. The truth is more complicated. Even if we were on track to reach the "limits" of atmospheric carbon, we have no certainty that they will help us avoid a tipping point - merely a likelihood, the estimates of models that even the scientists themselves admit are probably inadequate to deal with the fact that climate change is happening now, far faster and harder than anyone ever expected.

We cannot know exactly what will happen, but the fact that we cannot know things exactly doesn't mean that we can't know anything, or that we have no way of making any kind of rational choice. While Occam's Razor, for example, is an imperfect logical tool, it also has real merit here - the fact that climate change seems on its own to be accellerating rapidly means that in our search for solutions, we should focus not only 30 or 50 year plans, but on doing as much as we can to ameliorate the harm we've done as rapidly as we can. Instead of focusing on CAFE standards and hope for technological breakthroughs, we are simply going to have to accept that having altered our world irrevocably, we have no choice but to live in that world - and thus, to ensure in any way we can, that the world remains livable for those who live today and those who will come after us.

Sharon