For those seeking to deny the realities of climate change, a popular counterpoint is simply: “The climate has changed before.” A straightforward argument and difficult to refute. Thankfully, the ever amusing xkcd comic has just released a new visualization showing just how misleading this statement can be.
For the uninitiated, xkcd is the brainchild of Randall Munroe, a cartoonist, physicist and former NASA roboticist. The darling of scientists and nerds everywhere, Munroe has knack for humorously and insightfully illustrating complex scientific topics. From fun themes like time travel to foundational scientific concepts like DNA, Munroe has dabbled across disciplines.
For Monday’s comic, xkcd tackled climate change. Looking back as far as the last glaciation—when Boston was buried under a mile of ice and glaciers stretched towards Manhattan—Munroe traces changes in the Earth’s climate up through modern times. Along the way, he tracks how the climate responds to melting ice sheets, changes in the Earth’s orbit and changing ocean circulations, all relative to the average temperature of the late 20th century.
Munroe aptly shows what the statement, “the climate has changed before,” actually means. As you continue to scroll down and down and down, it becomes obvious that past climatic changes progress slowly and incrementally. The sudden final veer to the right at the bottom of the graphic, which represents human-caused climate change, is a stunning contrast to the otherwise minute changes.
With two climate items of note headlining the news this week, the new comic could not have been timed any better.
On Monday, NASA announced that August 2016 was the warmest August ever recorded in 136 years of recordkeeping. August 2016 actually wound up tied with July 2016 as the warmest month ever recorded, despite the fact that the seasonal temperature cycle typically peaks in July.
On the same day, Brazil announced that it had ratified the Paris climate agreement, lending a dash of optimism to the foreboding data released by NASA. Home to the largest tropical rainforest on Earth, Brazil has the third-largest emissions of any country to sign the agreement, behind only the U.S. and China. In order for the climate agreement to enter into force, 55 countries accounting for 55 percent of global emissions must sign and ratify, or otherwise approve, the agreement. Not including Brazil, 27 countries representing just over 39 percent of global emissions have signed and ratified the agreement, according to the World Resources Institute. The announcement that Brazil has now ratified the agreement is significant.
With these things in mind, take a scroll through time and check out Munroe’s comic: