We talked about the distant past on Earth, 65+ million years ago, back in the Cretaceous when global carbon dioxide levels were 4-5 times what they are now. Yes, the climate was warmer and yes, life on Earth and in the ocean thrived on a warmer planet with more carbon dioxide in the atmosphere. Given that, he asked, why should we be concerned with a changing (warming) climate today? Won't life thrive under warmer conditions?
Yes, it will...eventually.
It finally occurred to me that what's not talked about much in the media is the rapidity of the changing climate versus the relatively slow rate of species adaptations that we see around us.
The species on this planet now have evolved, for the most part, in a climate that is overall cooler and lower in carbon dioxide than existed during the dinosaurs' times. The climate we have now took millions of years to cool from its Creatceous high, and that overall gradual cooling allowed species enough time to evolve in response. Some species didn't survive the cooling climate. Other, new species evolved that were better-adpted. But this all took many millions of years.
The pace of warming today is fairly rapid, much more rapid than scientists even 20 years ago were predicting thanks to our reliance on carbon-rich fuels. The warming is more rapid than what my professors and I, working on glaciers in Alaska and Greenland in the 1990s, ever thought could be possible. So the biggest problem for plants and animals really is that the climate may be changing faster than those species can evolve to cope with that change. Life on Earth will survive our warming planer, but it will look very different from what we know today.
We may have to make peace with some amount of species loss. This isn't doom-and-gloom but reality. Humans have impacted the Earth so much already, not just in terms of greenhouse gases but also by our ever-expanding human populations, that it may already be too late for some plants and animals. Should we try to minimize the impacts? Yes, definitely, but we must also face the reality that with humans around, the Earth won't be what it was 5 million years ago. It doesn't have to be bad with us here, but it will be different.
Pika on granite boulder, Mt. Evans, Colorado
If we choose to try to save as much plant and animal life as possible, we may need to take a more active role in managing ecosystems. For example, the pika, a small, alpine rodent living in North America, cannot survive in warm temperatures. With climate warming, scientists are noting that pika populations are dwindling in places such as California and the Great Basin of the United States. Because pikas can't move from one mountain range to another themselves, if humans want these cute rabbit relatives to survive, we may need to take it upon ourselves to relocate them. This is just one example of the questions we face as the climate warms.
We can (and in my mind, should) take responsibility for minimizing our impact on the environment as much as possible, not just for the plants and animals, but for us too. Whether we realize it or not, our survival is intertwined with our environment: we are a part of nature, and for our own survival, we need a world that is healthy in order to survive as a species.
The real question is: how will we as humans cope while the climate comes to some sort of new equilibrium? We are adaptable, perhaps the most adaptable species on the planet. We have some fairly advanced thinking skills that we will need to employ to solve the problems as they arise. A changing climate will mean that we will have to learn to work together for perhaps the first time in our history. Can we do this? Yes, I believe we can.
Will we? Well, that's up to us...
For more information, see:
- Joseph A. E. Stewart, John D. Perrine, Lyle B. Nichols, James H. Thorne, Constance I. Millar, Kenneth E. Goehring, Cody P. Massing, David H. Wright.Revisiting the past to foretell the future: summer temperature and habitat area predict pika extirpations in California. Journal of Biogeography, 2015; DOI:10.1111/jbi.12466