Climate Change Impacts Daily Weather On Global Scale
Av. global temp. on Jan. 2, 2020 was 1.3 degrees F warmer than 1979-2000 av. Map: ClimateReanalyzer.org via weather.com
For years, weather forecasters have been reluctant to say that any single weather event was caused by climate change, but have been increasingly willing to say the severity of weather events are impacted by it. Now, however, scientists who have studied global weather data say that beginning in 2012 “on the basis of a single day of globally observed temperature and moisture, we detect the fingerprint of externally driven climate change, and conclude that Earth as a whole is warming.”
Why This Matters: The difference between weather and climate has often been explained as: “Climate is what you expect, the weather is what you get.” This distinction helps people to understand the difference between day-to-day weather variability (such as cold days in summer and warm in winter) and the long-term signs of climate change — global monthly and annual temperature averages, for example. When we talk about climate change, we can now explain it as something that is immediately apparent — not something that takes years to comprehend. This should help in rebutting climate deniers insofar as they were resting on arguments about weather variability.
Apparently President Trump’s tweets about wanting “good old fashioned global warming” on extremely cold days motivated the authors to look at global statistics and climate model simulations to evaluate how daily temperatures and humidity vary around the world. What they found, according to one of the authors is that “[g]lobal mean temperature on a single day is already quite a bit shifted. You can see this human fingerprint in any single moment.” The Washington Post’s Andrew Freeman concluded that the study implies “that research aimed at assessing the human role in contributing to extreme weather events such as heatwaves and floods may be underestimating the contribution.” Moreover, the “fingerprint” of climate change on daily global weather could still be detected in regional patterns of temperature and humidity even if when the researchers took factored out the global warming trend.
Stanford University climate scientist Noah Diffenbaugh, who was not part of the research team, told The Post that the new study advances our understanding of climate change’s effects. “The fact that the influence of global warming can now be seen in the daily weather around the world — which in some ways is the noisiest manifestation — is another clear sign of how strong the signal of climate change has become,” he said in an email.