It’s a cold fall day in north Georgia, which isn’t unusual. But it’s more unusual than it used to be.
Global climate change is, by definition, global. But as individual human beings, we don’t witness or experience the change globally; we experience at a micro-local level, right outside our doorsteps. And the evidence of a rapid transformation is pretty clear.
For example, spring comes earlier and earlier. Here in Georgia, researchers say, trees on average reach “first leaf” some four days earlier than they did from 1961-1980. That may not seem like much of a change, but it’s a change that has come very quickly and that shows every sign of continuing. By the middle of the century, spring may come to metro Atlanta as much as two weeks earlier than in the historical data.
And then there’s the issue of temperature extremes. In a stable climate, record lows and record highs ought to occur in roughly equal numbers. But in looking at the Atlanta data, that’s not what you find.
Since 2000, we’ve set 47 record highs and just 14 record lows. Since 2010, we’ve set 21 record highs and just one record low.
Nationally, record highs have outnumbered record lows by roughly a 2-1 ratio since 2000, which means that Atlanta’s ratio of more than 3-1 is somewhat unusual. Our concrete-heavy urban footprint may be one reason why. That illustrates why local data shouldn’t be used to characterize a global phenomenon, but again, it’s also the change as we in metro Atlanta have experienced it.
A third way to document the change is through shifting plant-hardiness zones as issued by the U.S. Department of Agriculture. Certain plants are intolerant of too much heat; others of too much cold. Rhododendrons, for example, need cold winter nights as part of their flowering process, and all of Georgia once provided suitable habitat for “rhodies.” Thanks to climate change, that’s no longer the case. The same is true of an even more iconic plant, the Georgia peach.
According to USDA maps updated with temperature data compiled through 2005, growing zones in Georgia have shifted 50 to 100 miles northward since the 1990 update. As a result, the Georgia coast now has a climate more akin to central Florida, and has become too warm for most varieties of rhododendrons or peaches to thrive.
People who spend a lot of time outdoors — gardeners, farmers, hunters and fishermen — will often tell you that they don’t need official maps or research to document such changes. They’ve seen it themselves, and that itself is pretty stunning. Skeptics of climate change often point out that the climate has never been stable, and they’re right. But scientists say it has never changed at a rate that would be noticeable within the range of a human lifetime.
According to scientists at the National Oceanic and Atmospheric Administration, “the current rate of global climate change is much more rapid and very unusual in the context of past changes.” In fact, if warming continues at the rate projected in climate models, “there is no evidence that this rate of possible future global change was matched by any comparable global temperature increase of the last 50 million years.”
We’re living through that change; we’re witnessing it firsthand. And we’re doing very little to stop it.
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