My extended family tells me they're getting a little depressed about hearing all the bad things that might happen from global warming. So I guess it's time to point out that maybe it's not as bleak as it seems. Here's the good news. We live in a world that, despite the unwitting impacts of humanity, is still in pretty good shape. If you define wilderness as places that have fewer than five people per square km, with at least 70% of the natural vegetation intact, in patches of at least 10,000 square km, you are talking about 46% of Earth's land surface. That's not perfect, but it's pretty good, and offers reason for hope. Humanity also clearly values unspoiled places as emotional touchstones, as evidenced by some 12% of Earth's land being designated as national parks, reserves, or similarly legislated areas where some aspect of nature is protected. At least some of those areas are still ecologically intact to the extent that they are working very much as they were long before modern society got its hands on them. The Yosemite area still has pretty much the full complement of mammal species it had in John Muir's time. Yellowstone still has nearly all the mammals that have inhabited the park for at least three thousand years. In Africa, there are lots of charismatic megafauna left, and in fact overall community structure in many nature reserves there is not too different than it has been for tens of thousands of years. Bottom line: there's still an awful lot worth saving out there. We may be looking at the brink, but we're not over it yet. So far we've been reasonable, if far from perfect, stewards of nature. We don't want to blow it now, and we could in an instant. That's why the danger signs we're seeing in Earth's special places are particularly noteworthy—shifts of Yosemite's species to higher ground as climate heats up, decline in Yellowstone's amphibian species as drought hits the park year after year, and dwindling populations of large animals in South African parks as the dry season gets too long. These are early warning signs of heatstroke for nature, but it doesn't have to be fatal. Which brings us to the second bit of good news—we can do something to prevent the worst consequences of global warming, including consequences for nature. A critical piece of the solution is to take action to slow Earth's heat-up—and that means at the personal level, the corporate level, and at the national and international levels. For nature, we will also have to implement new conservation strategies to account for some amount of global warming that is inevitable. Lest you think it's un-doable, remember two things.
- Individual actions really are important. Just for example, changing light bulbs to CFLs. Multiply out the lightbulbs changed by hundreds of millions of households and businesses, and estimates of how much CO2 just that one action would keep out of the atmosphere range from 1.6 gigatons over 25 years, to saving as much as 2.4 gigatons over 10 years. To put that in perspective, around 3 gigatons is about what seems likely be added over the next 10 years if business goes on as usual.
- Never underestimate what people can do when they put their minds to it.