Dear Science,
Is global warming real? I would love to assume it is, because everybody I know claims it must be real and that the ice caps are melting, etc. But after the whole controversy with the hockey-stick graph and after having a look at some websites, I don't know what to believe anymore. Please help.
Confused Skeptic
Your unwillingness to simply accept global warming as true, just because your friends believe it to be so, is impressive. This is the starting impulse of any decent empirical mind. Science is—at its very core—the testing of ideas with facts. The idea here is a big one: human activities, particularly the release of greenhouse gases into the atmosphere, causing deleterious changes to the world climate and the health of the planet's biosphere.
The question is a fundamentally difficult one to answer. The planetary climate contains a nearly indecipherable degree of randomness and complexity—the present and future state a product of geologic, solar, and previous patterns of climate, and the effects of living things (human and nonhuman), among others. A run of cold days, or even cooler years, does little to disprove (or prove) the core idea: Humans are changing the climate in ways that are going to hurt us.
What do we know? The atmosphere has measurably changed since the advent of the industrial revolution. A variety of heat-trapping gases are now in vastly higher concentrations than before human activities began to impact the atmosphere. There are well-described and proven ways that these gases can change how the atmosphere interacts with the geology, the sun, and living things. For example, we can already observe devastating changes in the oceans. Much of the carbon dioxide released by the burning of fossil fuels has dissolved into the seawater, becoming carbonic acid—causing a measurable and worrisome drop of the pH of the water off the Pacific Northwest coast. We're already skittering close to the pH at which shellfish, including the microscopic plankton that support the entire ocean ecosystem, will not be able to survive.
Science can still think back to one of the more elegant studies on the temperature effects of carbon emissions, using the grounding of the all airplanes in the United States after 9/11 as a giant experiment—determining that all those jet emissions keep nighttime temperatures higher than they should be, proving one of the theoretical consequences of climate change.
Climate change is real enough, with enough backing observations and theory, to run with the assumption that it is most likely true—but probably more complex than we realize right now. Science recommends the UNEP climate change website as a place to start if you wish to fill your skeptical curiosity with more data and follow the latest research on the subject.
Quizzically Yours,
Science
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