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tivists-distort-the-evidence/ ------------------ Subscribe to our YouTube channel: https://www.youtube.com/ReasonTV?sub_confirmation=1 Like us on Facebook: https://www.facebook.com/Reason.Magazine/ Follow us on Twitter: https://twitter.com/reason Reason is the planet's leading source of news, politics, and culture from a libertarian perspective. Go to reason.com for a point of view you won't get from legacy media and old left-right opinion magazines. ---------------- Many officials and climate activists claim we have only 12 years to act on global warming. Where does this figure come from? A 2018 Special Report by the Intergovernmental Panel on Climate Change (IPCC). The second sentence of that document reads, "Global warming is likely to reach 1.5 degrees C between 2030 and 2052 if it continues to increase at the current rate." The 12-year figure comes from subtracting the year of the report, 2018, from the earliest possible date of 1.5 degrees C warming, 2030.  The problem is that this was a statement about the past, dressed up to suggest that it's about the future. It's not about what will happen; it's extrapolating from what has already happened. Actual temperatures in 2030 will depend on whether warming speeds up or slows down, and also on whether the year is warmer or colder than the long-term trend. Why the 22-year range? The authors of the IPCC report defined the current rate using data from 1960 to 2017. Using the NASA Goddard Institute for Space Studies (GISS) land-ocean temperature series that underpins most popular reporting about warming, global excess temperatures were 0 in January 1960 and 0.94 degrees C in December 2017. So the Earth has to warm another 0.56 degrees C to reach 1.5 degrees C. Some fifth-grade math tells us that should happen in 34.55 years if warming continues at the same rate. We'd hit 1.5 degrees C on July 21, 2051. Different measurements might give a couple of years either way, but not 22 years. The range of 2030 to 2052 is not about how warm the earth is but who's responsible for the change in temperature. The figures reflect "anthropogenic warming," or warming rooted in human activity. By citing a range of 2030 to 2052, the authors are indicating a high level of uncertainty. They're not sure how much of the 0.17 degrees C per decade warming is "anthropogenic," or rooted in human activity. They think it's possible that humans are warming the Earth 0.3 degrees C and some unknown factor is actually cooling the Earth 0.13 degrees C. (The IPCC declined to make any of the report's authors available for an interview). If you think the problem with global warming is hotter temperatures (melting ice, rising sea levels, and other physical effects), then you should care about the year 2052, not 2030. But if you think the problem with global warming is that humans are tampering with something pristine—and you only consider the worst possible scenario—then 2030 is your date. Focusing on anthropogenic warming suggests that what's happening in the real world matters less than who's at fault. Produced and edited by Justin Monticello; written by Monticello and Aaron Brown; camera by Zach Weissmueller; graphics by Isaac Reese; audio production by Ian Keyser. Music: Aerial Cliff by Michele Nobler, Land of the Lion by C.K. Martin, Thoughts by ANBR, Flight of the Inner Bird by Sivan Talmor and Yehezkel Raz, and Run by Tristan Barton.