No wonder so many scientists are at their wits’ end when it comes to climate change: Despite an overwhelming scientific consensus that the planet is warming—and that human activity is much to blame—the public remains skeptical. In fact, one poll indicates that nearly 2 out of 5 Americans believe global warming is just a hoax.
Not to mention that some of those climate change deniers are member of Congress.
So the leading science panels in the United States and the United Kingdom have released a plain-spoken primer on the subject, now available in print and online. The publication aims to be scientifically sound but unflinching. It confirms that human activity, primarily the burning of fossil fuels since the dawn of the Industrial Revolution, have caused a 40 percent increase in heat-trapping carbon dioxide in the atmosphere. In the 20th century, that marked a 1.4 degrees Fahrenheit rise in the average surface temperature of Earth. If emissions continue unabated on their current trajectory, the report notes, scientists are “very confident” that by the end of the 21st century, the planet will have heated up an additional 4.8 to 8.6 degrees.
Say, hypothetically, that the whole world suddenly stopped burning fossil fuels overnight? Problem solved? Not by a long shot—in fact, the report says temperatures would still remain elevated for about a thousand years. And sea levels would continue to rise for hundreds of years beyond even that.
“The current CO2 -induced warming of Earth is therefore essentially irreversible on human timescales,” the report declares. “The amount and rate of further warming will depend almost entirely on how much more CO2 humankind emits.”
The 36-page report was produced by the National Academy of Sciences and The Royal Society, and its lead U.S. author is UC Berkeley atmospheric science professor Inez Fung. The goal was to be succinct—as Fung told The Daily Californian, “you don’t have to wade through a thousand pages to get to what we’re talking about.”
Organized with a Q&A format, it asks and answers twenty common questions, including “Climate is always changing. Why is climate change of concern now?” and “Does the recent slowdown of warming mean that climate change is no longer happening?” and “If the world is warming, why are some winters and summers still very cold?”
Some responses address the seemingly obvious, such as why a few degrees of global warming matter that much:
“Both theory and direct observations have confirmed that global warming is associated with greater warming over land than oceans, moistening of the atmosphere, shifts in regional precipitation patterns and increases in extreme weather events, ocean acidification, melting glaciers, and rising sea levels (which increase the risk of coastal inundation and storm surge.) Already, record high temperatures are on average significantly outpacing record low temperatures, wet areas are becoming wetter as dry areas are becoming drier, heavy rainstorms have become heavier, and snowpacks (an important source of freshwater for many regions) are decreasing. These impacts are expected to increase with greater warming and will threaten food production, freshwater supplies, coastal infrastructure, and especially the welfare of the huge population currently living in low-lying areas.”
To those unconvinced that humans are responsible, the report explains how scientific inquiry works—and concludes that both the fundamental physics of greenhouse gases and “fingerprint” studies isolating unique factors show that recent change can’t be due only to natural causes such as volcano eruptions or variations in the sun’s output.
In the past decade, American public opinion about the threat of global warming has become a partisan divide. Republicans are far less likely to believe humans play a significant role in climate change, or to regard it as a problem. But Gallup and other pollsters find that gap is beginning to narrow a bit.
“As two of the world’s leading scientific bodies, we feel a responsibility to evaluate and explain what is known about climate change, at least the physical side of it, to concerned cititzens, educators, decision-makers and leaders,” said Academy of Sciences president Ralph Cicerone, “and to advance public dialogue about how to respond to the threats of climate change.”