Question submitted by Daniel Rose
Because there is a growing national and global conversation on climate change, with major world figures like the Pope joining in, you are likely to encounter people who do not know basic climate science or actually “know” things that are not true. In particular, certain flawed arguments against the science of human-caused climate change have become very commonplace.
These myths have become popular for two key reasons. First, most of them are repeated again and again by the disinformation campaign funded by the fossil fuel industry. Second, they sound plausible on the surface.
Anyone who plans to talk about climate change with their friends or family or colleagues should read my Oxford University Press primer, “Climate Change: What Everyone Needs to Know” and spend some time at the website SkepticalScience.com. Skeptical Science tracks and debunks the most popular climate science myths. It provides both simple and more detailed responses to all of the myths, complete with detailed citations of and links to the recent scientific literature. It even has an app for that purpose. Furthermore, it also includes the best strategies for effective communications based on the social science literature. By permission, I will make use of their material below—with tweaks and additions—to provide short answers to the myths and questions you are most likely to hear (which are in quotation marks).
- “The climate has changed before” or “The climate is always changing.” This assertion is actually true, but it is meant to imply that because the climate changed before humans were around, humans cannot cause climate change. That is a logical fallacy, like saying smoking cannot cause lung cancer because people who do not smoke also get lung cancer. In fact, climate scientists now have the same degree of certainty that human-caused emissions are changing the climate as they do that cigarette smoking is harmful. The key point is that the climate changes when it is forced to change. Scientific analysis of past climates shows that greenhouse gases, principally CO2, have controlled most ancient climate changes. The evidence for that is spread throughout the geological record. Now humans are forcing the climate to change far more rapidly than it did in the past mainly by our CO2 emissions—50 times faster than it changed during the relatively stable climate of the past several thousand years that made modern civilization (and particularly modern agriculture) possible.
- “Warming has stopped, paused, or slowed down.” In fact, 2014 was the hottest year on record, until 2015 crushed it, and then 2016 easily topped 2016. The warming trend in the past two decades now exceeds the warming trend in the two decades before that. Also, empirical measurements of the Earth’s heat content show the planet is still accumulating heat. Global warming is still happening everywhere we look, especially the oceans, where more than 90% of the extra heat trapped by human carbon pollution goes.
- “There is no scientific consensus on human-caused warming”: In fact, our understanding that humans are causing global warming is the position of the Academies of Science from 80 countries plus many scientific organizations that study climate science. More specifically, surveys of the peer-reviewed scientific literature and the opinions of experts consistently show a 97%–98% consensus that humans are causing global warming.
- “Recent warming is due to the sun.” In fact, in the last 35 years of global warming, the sun and the climate have been going in opposite directions—with the sun actually showing a slight cooling trend. The Sun can explain some of the increase in global temperatures in the past century, but a relatively small amount. The best estimate from the world’s top scientists is that humans are responsible for all of the warming we have experienced since 1950.
- “Are surface temperature records reliable?” Independent studies using different software, different methods, and different data sets yield similar results. The increase in temperatures since 1975 is a consistent feature of all reconstructions. This increase cannot be explained as an artifact of the adjustment process, the use of fewer temperature stations, or other nonclimatological factors. Natural temperature measurements also confirm the general accuracy of the instrumental temperature record.
- “Isn’t Antarctica gaining ice?” Satellites measurements reveal Antarctica losing land ice at an accelerating rate, leading many scientists to increase their projections of sea-level rise this century. Why, then, is Antarctic sea ice growing despite a strongly warming Southern Ocean? The U.S. National Snow and Ice Data Center explained in 2014 that the best explanation from their scientists is that it “might be caused by changing wind patterns or recent ice sheet melt from warmer, deep ocean water reaching the coastline. . . . The melt water freshens and cools the deep ocean layer, and it contributes to a cold surface layer surrounding Antarctica, creating conditions that favor ice growth.”
- “Didn’t scientist predict an ice age in the 70s?” The 1970s ice age predictions you hear about today were predominantly from a very small number of articles in the popular media. The majority of peer-reviewed research at the time predicted warming due to increasing CO2
- “Climate change won’t be bad.” As the scientific literature detailed in this book makes clear, the negative impacts of global warming on agriculture, the environment, and public health far outweigh any positives. The consequences of climate change become increasingly bad after each additional degree of warming, with the consequences of 2°C being quite damaging and the consequences of 4°C being catastrophic. The consequences of 6°C would be almost unimaginable.
- “Can climate models be trusted?” A related question is, “Since we can’t predict the weather a few weeks from now, how can we predict the climate a few decades from now?” Although there are uncertainties with climate models, they successfully reproduce the past and have made predictions that have been subsequently confirmed by observations. Long-term weather prediction is hard because on any given day a few months from now or a few years from now, the temperature could vary by tens of degrees Fahrenheit or even Celsius. Similarly, there could be a deluge or no rain at all on any given day. The weather is the atmospheric conditions you experience at a specific time and place. Is it hot or cold? Is it raining or dry? Is it sunny or cloudy? The climate is the statistical average of these weather conditions over a long period of time, typically decades. Is it a tropic climate or a polar climate? Is it a rainforest or a desert? The climate is considerably easier to predict precisely because it is a long-term average. Greenland is going to be much colder than Kenya during the course of a year and during almost every individual month. The Amazon is going to be much wetter than the Sahara desert virtually year-round.