In his recent essay for Adirondack Explorer’s column, “It’s Debatable,” that was later re-published in the Almanack, John Droz presented more than an opinion that wind energy is a bad idea for the Adirondack Park.
He also slipped in a mention of the “AGW hypothesis,” meaning that the scientific consensus on “anthropogenic global warming” is mere guesswork.
We should not be surprised that he did so, because Droz has been associated with ultra-conservative, pro-fossil-fuel organizations such as The American Tradition Institute, known for denying the reality of human-driven warming and harassing climate scientists, and The Heartland Institute, which has mailed climate disinformation to thousands of school teachers nationwide to spread confusion and doubt about the science.
Furthermore, despite the essay’s deceptive bio, he is not what most scientists would call a physicist because he lacks a Ph.D. or requisite peer-reviewed papers in physics, and he is certainly not a climate expert. I am, however, surprised that the Adirondack Explorer presented such a discredited claim from the denial-and-doubt network as one legitimate side of a scholarly debate. It is not, and here’s why.
The consensus position that global average warming during the last half-century is real and mostly caused by humans, shared by the vast majority (ca. 97%) of truly qualified climate scientists, is the result of huge amounts of peer-reviewed research from many independent branches of the sciences that have been conducted worldwide over many years.
In this country alone, highly reputable organizations such as the American Physical Society, the American Geophysical Union, and the American Association for the Advancement of Science agree with it, as do the insurance industry and the United States military. Even the fossil fuel industry is on board; Exxon researchers were among the first to document it with an eye toward exploiting an increasingly ice-free Arctic. What is this evidence that convinces all but those who don’t understand it or choose to ignore it? Here are some of the key aspects that have convinced me as a skeptical scientist.
How does it work? Basic physics. Greenhouse gases such as carbon dioxide trap heat that rises from land and sea surfaces that have been warmed by the sun, through the “greenhouse effect.” Adding more heat-trapping gases to the atmosphere will of course warm it up, and the more of them we add the warmer it will get. We also know that carbon dioxide concentrations are rising because they are measured in detail at multiple locations. These points alone should lead a reasonable person to expect global warming to result from the burning of so much fossil fuel. But there’s more to consider if that’s not convincing enough.
How do we know that the carbon dioxide is increasing because of us? Basic physics and chemistry. We know about how much coal, oil, and natural gas we burn and how much carbon that should release, and it fits with the observed rise. Oxygen levels are declining as carbon dioxide increases, a clear sign that this is the result of combustion. And decreasing concentrations of carbon-13 isotopes in the air identify the carbon atoms in the excess carbon dioxide as coming primarily from fossil fuels. Any one of these points, each the result of rigorously peer-reviewed research, makes a strong case in its own right.
How do we know it’s warming? More physics. Greenhouse warming has made thermometers register higher temperatures at thousands of weather stations all over the planet. Deniers often blame the rise on a “heat-island effect” due to urbanization, as if real experts don’t know enough to take it into account. Most stations show no such effect, as our own rural Adirondack records clearly indicate, and the city-free oceans are also warming.
These records are far too numerous, well-documented, and widely dispersed to be due to some fanciful conspiracy or supposed incompetence among the scientists who analyze them, and nowadays satellite observations further support those data. Meanwhile the stratosphere has cooled while the lower atmosphere warmed, showing that the excess heat is being trapped from below by greenhouse gases rather than simply coming in from the sun. Again, this is abundant, powerful, peer-reviewed evidence.
How do we know it isn’t just natural cycles? Paleoclimate data from historical documents, ice cores, tree rings, and sediment deposits all over the planet. We know these cycles well, and none of them explain the warming of the last half century. The sunspot cycles are too fast and orbital cycles are too slow. Climate deniers often point to the so-called “Little Ice Age” and claim that we are simply recovering from that natural cool period, but it ended more than a century ago, well before the warming of the last half-century. Sediment cores from Arctic lakes show that the ice-free conditions they now experience in summer have not happened for thousands of years previously and are therefore not due to cyclic changes.
Each of these conclusions represents masses of peer-reviewed evidence that was gathered by sincere, skilled professionals, often at significant personal risk. I have faced my share of hazards during my research around the world and several of my colleagues have been injured or killed in the field, so I have little patience with armchair naysayers who disparage such hard-won science.
But… but… how do we know? If this much evidence doesn’t convince you, then there’s not much more I can tell you. Except that you’ve been watching the changes happen with your own eyes if you’ve lived in the Adirondacks long enough and paid thoughtful attention. Ice on our lakes has been forming later and melting earlier, as documented in local ice-out contests and nature journals. The main basin of Lake Champlain failed to freeze completely only 3 times during the 1800s. Now it is ice-free more often than not. Our wildlife is responding to earlier springs, from migrating salamanders to robins. Local weather stations show that our rainstorms are becoming stronger as we also learned the hard way from tropical storm Irene. Farther downstate, the Battery Park tide gage in Manhattan shows that sea level rose enough from meltwater and thermal expansion of warming oceans to increase the storm surge damage from Hurricane Sandy. Some of my conservative friends have recently considered lobbying the state to push deer-hunting season later in the fall because, they say, the rut is coming later. They might not call it “global warming,” but whatever they may call it they see it happening, too.
As one of many scientists who were initially skeptical of early claims that recent global warming is mainly due to human activity, I at first sympathized with those who called it a mere “hypothesis.” Back then, the honest skepticism was healthy because it encouraged us to re-visit the science and make sure it was sound. Now that we have done so and the various bits of evidence have become a massive interlocking structure, real skeptics have changed their minds and stand by that mountain of evidence.
The few detractors who still linger on the fringe are not operating in the best interests of science or society but are instead mistaken, pushing their personal or political agendas, or both. There is plenty for us Adirondackers to debate when it comes to the pros and cons of wind energy in the Park. But we all lose when science itself is abused in the process.
Graph of Temperature data from four international science institutions: NASA’s Goddard Institute for Space Studies, NOAA National Climatic Data Center, Met Office Hadley Centre/Climatic Research Unit and the Japanese Meteorological Agency. Graph produced by Earth Science Communications Team at NASA’s Jet Propulsion Laboratory | California Institute of Technology.