Which Came First–CO2 or Rising Temps?
The answer to what is causing global warming sounds simple, right? Carbon dioxide is a greenhouse gas; greenhouse gases warm the Earth; we are adding carbon dioxide to the atmosphere; the Earth’s surface is warming. Ispo facto, carbon dioxide is the culprit. And since we are responsible for adding carbon dioxide to the atmosphere, it’s our fault.
But here’s the catch: A surprising finding from ice cores taken from glaciers in the Antarctic shows that, for the past 800,000 years, carbon dioxide change has actually lagged temperature change — not preceded it — by an average of 800 years, ranging from centuries to millennia. What’s more, three Norwegian scientists authored a paper published in Global & Planetary Change in 2012 showing that carbon dioxide change has recently lagged temperature change by 11 to 12 months. Something that lags something else cannot be the cause of that something else. Although Earth’s surface temperature has risen some since 2000, it has not closely tracked the great increase in carbon dioxide. Temperature has wobbled with perhaps a slight increase. Meanwhile, carbon dioxide is increasing steadily and rapidly.
These new facts tell us that carbon dioxide cannot be the primary cause of the current warming, so that the burning of fossil fuels also does not appear to be the primary cause of global warming. They find that this data in no way disproves the role of CO2 in planetary warming over time.] Instead, current data suggest that changes in Earth’s surface temperature more closely track changes in the sun’s output of radiant energy.
Having done research on possible ecological effects of climate change for many decades, and having been involved in some of the climate models, these results are especially surprising to me. Until the beginning of the 21st century, the weight of evidence seemed to be that carbon dioxide and other greenhouse gases produced by modern technological society were the primary cause of global warming. I wrote articles and gave talks bringing those points to the public. But being well aware of one of Barry Commoner’s famous three informal “laws” of ecology — that you can’t do just one thing — I never expected the causes of climate change to be as simple as the popular press, politicians and pundits have made it out to be. The causes of climate change are more complicated. Nor did I ever expect that the climate change issue would be transformed into a morality play focusing on a blame game — who’s at fault for causing it, who has the audacity to either believe or not believe that the warming is human-caused. Nor did I expect to find my scientific colleagues on both sides of the debate accusing each other of improper and immoral behavior.
Thus, in my new book, The Moon In the Nautilus Shell, I am rather agnostic about human-induced global warming. We are just starting to try to understand our planet’s huge and complex life-supporting system, and we haven’t gotten as far as we would like. The causes of climate change on a planet with life and with liquid, gaseous and frozen water are more complicated than popular discussions suggest.
The problem today is that the national public conversation about nature is focused almost exclusively on global warming. Meanwhile, we are messing up the environment in many ways that need our attention.
Invasive species affect biological diversity broadly, both on land and on water. For example, citrus greening, a disease from China, threatens to destroy all of America’s citrus agriculture. The Burmese python from Asia is completely changing the Everglades ecosystem. Our air, water, and soils continue to be polluted. We are seriously overharvesting many kinds of fish, some to the point that they are no longer commercially viable. Large tracts of tropical rain forests are being cut down. Some are converted to oil palm plantations with the claim that these will produce biofuels that will help with global warming. But the destruction of those forests eliminates habitats of many species, including the orangutan, the very things that efforts to halt global warming were supposed to help. Our highly productive farming is threatened by a coming lack of phosphorus fertilizer and water for irrigation, as we use up available mined supplies.
Concern over global warming has led to promotion of shale gas, not only because it is cheap but also because, when burned, it produces less carbon dioxide than coal does. This has led to the promotion of clean coal for the same purpose. But more mining for these fossil fuels increases environmental impacts, takes away habitats and migratory routes and adds pollutant chemicals other than carbon dioxide to the environment.
We need to change the conversation. We need to discuss solutions to here-and-now problems we have some control over. Activists who have not seen the latest scientific findings I have written about here might get up to speed and join the pursuit of this broader goal to the benefit of the environment and the well-being of our society.
*Dr. Botkin’s views do not reflect the views of E Magazine, but are part of an ongoing and necessary conversation on climate change.