|February 13, 2009|
The Climate Change Imperative: Part 2
Why We Must Stop Global Warming
[Part 2 of a two-part article.]
In Part 1 of this article, I detailed some of the recent extreme weather events and argued that "climate change" is a more appropriate label than "global warming" because what we experience is an unpredictable and changing climate more than a uniform increase in temperatures.
In this part, I explore some of the risks that climate change poses, beyond rising sea levels, and argue that scientific uncertainty about anthropogenic global warming should be our reason for action, not an excuse for inaction.
Climate and Crops
Crop yields are incredibly sensitive to temperature and rainfall. A mere one to two degree rise in temperature can reduce grain harvests, due to dehydration and poor fertility. For example, a study on wheat in India found that a two-degree Celsius rise in temperature led to a 37-58% loss in yields. Another study from the Philippines found that rice fertility was 100% at 940 F, but nearly zero at 1040 F. A third study from India found that for each degree Celsius rise in temperature, rice yields fell by 6%.
Research in the U.S confirms the sensitivity problem. A study by scientists at the Carnegie Institution found that a one degree Celsius rise during the growing season reduced the yields of both corn and soybeans by 17%. Another study by the University of Wisconsin-Madison in 2008 showed that a one degree Celsius rise cut corn and soybean yields by 13-16%.
Record heat and drought in Europe, the U.S. and India led to record grain worldwide shortfalls in 2002 and 2003.
Last year, floods and heavy rains in China, Bangladesh, India, Indonesia, Vietnam, North and South Korea, and the Philippines cut severely into the crop output of Asia.
Declining crop yields are only a highly visible example of the effects of extreme weather on the natural world, though. Changes in climate are killing off trees across the North American west, as drought and changing soil conditions lead to plagues of insects, disease and invasive species, as well as increasingly frequent and devastating wildfires. Hot-burning wildfires are actually scorching the topsoil, preventing new trees from sprouting.
Researchers on the subject have concluded that a rise in local temperatures was responsible for the tree die-off, after ruling out other factors such as air pollution and forest management practices.
Disappearing trees are only a part of a much larger dynamic: that of the gradual desertification of arid climates. In a new report released this week in New Scientist, climate scientists found that low-latitude weather systems are moving toward the poles, while the tropics are expanding. Detailed measurements of the altitude of the tropopause—the boundary between the troposphere and the stratosphere—found that after adjusting for natural variation from year to year, the edges of the tropics are moving toward the poles at a rate of roughly 70 kilometers per decade.
The team also found that their data matched the results predicted by a leading climate model when human emissions were taken into account, but didn't without them.
This observation matches well with apocryphal observations and scientific data showing that the climate that used to exist in, say, Missouri 40 years ago is now found in Tennessee, and that Tennessee's historical weather is now more likely in Kentucky.
As warmer weather marches north, the deserts of the American Southwest are slowly growing. A 2007 study published in Science showed that "a broad consensus among climate models" would bring conditions reminiscent of the Dust Bowl to the region by 2050, and that the deserts would eventually stretch all the way to San Francisco.
Putting the two studies together then, the desertification of Australia, an arid sub-tropical climate moving toward the South Pole, is essentially the flip side of the desertification of American Southwest, with its arid sub-tropical region moving toward the North Pole.
Unfortunately, plants and animals don't move at such a rapid pace, leaving them increasingly out of step with their environments. This in turn has a domino effect, further changing local ecosystems.
Changing and unpredictable weather patterns will not only transform our environment, but make farming increasingly difficult, and maintaining our infrastructure a nightmare. We have still hardly begun to recover from the damage caused by Hurricanes Katrina and Rita and Ike, which are believed to only the first of a series of increasingly severe storms in the Gulf due to its warming waters.
All considered, even "climate change" may be too nice a phrase.
What If The Science Is Wrong?
It's clear enough that we have a rapidly changing and increasingly chaotic climate, and rising global temperatures; about that there is little disagreement. The hot debate is about whether the burning of fossil fuels is responsible for it.
From the perspective of petroleum geology, it makes intuitive sense to think so. Releasing carbon into the atmosphere in just 200 years that took hundreds of millions of years to accumulate is bound to have some serious effects.
The available science on anthropogenic global warming is incomplete, to be sure, yet there is enough consensus to influence policy. In addition to the scientific community, the Pentagon, former officials from the CIA and the White House, many heads of state, even the chiefs of oil companies and automakers have agreed that CO2 emissions are a serious problem we must address.
But suppose the science on CO2 emissions is wrong. What if the climate changes we're seeing aren't caused by human activity, but by larger cycles we don't yet understand? If the science is incomplete, shouldn't we wait until it's more certain before going to all the expense of fighting emissions?
The answer is no.
Consider this: Humanity cannot accurately predict the evolution of a puff of smoke blown into a bell jar, even with modern mathematics and computing power. Modeling turbulence in a bell jar, let alone a hurricane, remains a major challenge. Small variations in complex, 3-D, chaotic natural systems quickly ruin our predictive capabilities, no matter how precise the model.
Science is still struggling to identify all the factors that affect the global climate, let alone model them accurately, or understand the complex interactions between them, or predict how they will change.
If we can't model the weather in a tiny controlled environment like a bell jar, how much faith should we have in our models of climate change?
The Precautionary Principle
The lack of absolute scientific certitude should be the very reason we take action on global warming, not an excuse for inaction.
With our very survival on the line, we would be wise to follow the precautionary principle, which boils down to "If you're not sure you can fix it, don't break it." Merely poking holes in the existing body of research, meager as it is, may be satisfying to global warming deniers, but is not an assurance that we know what damage we might be causing, or that we know how to fix it. By the precautionary principle, we should be absolutely certain that CO2 is not the problem before continuing to produce it.
Or perhaps we should follow a reformulation of Pascal's Wager, along the lines of "With the health of ourselves and the entire planet at risk, and insufficient knowledge about it, we should err on the side of safety."
By the time our models are capable of accurately measuring and predicting what will happen with the global climate, it could be far too late to do anything about it.
Indeed, it may already be too late. As I mentioned last week, a new study by a US team of environmental researchers, sponsored by the Department of Energy and published in the journal Proceedings of the National Academy of Sciences, found that even if carbon emissions were halted, global temperatures would remain high for another 1,000 years as the CO2 already in the atmosphere continued to warm the planet.
Instead, we should be employing all of the knowledge and tools at our disposal to address this potentially devastating threat.
If the Earth were threatened by a massive asteroid that might or might not hit us, but we couldn't be sure, would we argue about whether we should go to the expense of building a rocket to deflect it, or would we build that rocket just in case? Of course we would build it.
Perhaps the only difference is that we love to build fancy machines that go into space and blow stuff up, but we don't love having to give up our cars or change what we do.
Humanity is essentially conducting an unplanned, uncontrolled, and unexamined experiment with the global climate, with potentially catastrophic effects.
Should we not take a moment to ask why on earth we would ever take such a risk? And are we not now obliged to reconsider our choices?
If the world's leaders had sat down 150 years ago and decided whether or not to take a short, 200-year journey up and down the peak of fossil fuel use, potentially throwing the global climate into disarray, would they have chosen it? Would the farmers and the regular folk have gone along with that choice? The religious leaders?
Have we not pushed other species to the brink of extinction and beyond, without even considering the cascading effects that might have on the ecosystem? Are we not now at a tenuous point in our own survival, with shortages of water, energy, and food creeping around the globe?
Can we do no better than blindly stumbling down the doomed path we're on?
Finally, if we had the option to end the age of fossil fuels in our lifetime, and take a greener path, how could we possibly not take it?