Thanksgiving is usually a day for turkey, football, and a very big parade in New York City. This year it is also the day before the release of the 4th National Climate Assessment. Why it is being released (or buried) the day after a major holiday is perhaps the subject of a future article, but I digress. Because it is cold, I also noticed a ton of rampant zombie theories about climate change this week. Zombie theories are ideas that have long been refuted by science community but live on in social media like some bizarre climatological episode of The Walking Dead. Record cold temperatures are being experienced this Thanksgiving weekend in the Northeast United States. The Boston Globe reported that Hartford, Worcester, and Providence experienced the coldest Nov. 22nd on record according to the National Weather Service. Cold days or weeks always bring out Tweets like "It's record cold, what happen to global warming?" or "I have 20 inches of global warming in my yard." These are cute Tweets, but they reveal a basic lack of understanding of science and can make for a tiring Thanksgiving dinner table conversation. Here are 3 reasons I believe such thinking happens.
The first reason is that many people do not understand the difference between weather and climate. I will turn to the American Meteorological Society Glossary for some basic definitions:
Weather: The state of the atmosphere, mainly with respect to its effects upon life and human activities...As distinguished from climate, weather consists of the short-term (minutes to days) variations in the atmosphere....Climate: The slowly varying aspects of the atmosphere–hydrosphere–land surface system. It is typically characterized in terms of suitable averages of the climate system over periods of a month or more, taking into consideration the variability in time of these averaged quantities.
Ok, let's focus on the graphic above which shows near surface temperatures across the globe on Friday, November 23rd. The blue in the Northeast United States indicates that the "weather" pattern "this week" gave that part of the country record cold temperatures. If you look at the anomaly map below, it provides even more context for just how cold relative to an average period. More importantly, it shows that there are other places that are not anomalously cold this week. Yet, some people used that blue area to make a sweeping statement about the entire globe. Such statements are akin to saying world hunger ended because your family ate dinner last night.
I contemplated leading with the anomaly map, however, it tends to cause confusion, lectures, and debate in social media. I understand them, but the average person probably does not. These map are generated using awesome online tools at ClimateReanalyzer.org. This website is a part of the Climate Change Institute at the University of Maine. Their website points out:
The weather maps shown here are generated from the NCEP Global Forecast System (GFS) model. GFS is the primary operational model framework underlying U.S. NOAA/NWS weather forecasting. The model is run four times daily on a global T1534 gaussian grid (~13 km) to produce 16-day forecasts. Here, we use 0.25°x0.25° (~30 km) output grids available from NOMADS, and calculate daily averages from eight 3-hourly timeslices starting at 0000 UTC.
The anomaly map is referenced to the period 1979-2000 using reanalysis of the NCEP Climate Forecast System (CFSR/CFSV2) model. Normal periods are 30-year windows used to generate climate anomalies. ClimateReanalyzer uses 1979-2000 rather than 1981-2010 because it predates significant Arctic warming. Their website includes a discussion of model biases to consider as you consume the maps.
The second reason people may confuse cold days and climate change is that people (Wait for it....................) forget that the Northern Hemisphere is starting to tilt away from the Sun in late Fall and Winter. This causes seasons. We are supposed get cold weather during this season. As I wrote previously in Forbes,
our weather is governed by a series of undulations or wave patterns. The "valleys" (troughs) in those waves allow cold, dense air to ooze into the U.S. The "hills" (ridges) in the waves are typically associated with warm conditions....The other thing to point out is that because one part of the world is cold (in that valley), there is likely another part of the world experiencing abnormally warm conditions (in the hill part of the wave pattern)... If you need a visual of how our three-dimensional atmospheric wave patterns work, consider what happens when you press down on a water bed mattress (for us older folks) or an inflatable bouncy house. One part goes down, another part goes up.
These undulations typically have a lot more amplitude during this season. The "not-so-breaking news" is that even as our climate system warms, we will still have winter weather.
Misperceptions, in general, are the third reason that uncle might say climate warming is "fake news." There is a wide spectrum of science literacy in the United States. A quick reflection on your middle or high school science class should make the point here. Because of this range of science literacy, there is a large segment of the population who believes that it cannot get cold in deserts, the sun revolved around the Earth or that tsunamis are weather phenomena. Weather, which is steeped in complex physics and mathematical concepts, is taught at a very basic level in K-8 (4 basic fronts and 4 basic clouds for the most part). I know because I see weather units throughout K-8 classes that I visit. The amount of climate instruction can vary even more (even within meteorology programs at the collegiate level).
I try to use analogies like "Weather is Mood, Climate is Personality" that I got from my University of Georgia colleague Dr. John Knox years ago. When speaking to Congress or the Rotary Club, I find it far more effective at explaining a cold day within the context of climate change than going through the Navier-Stokes equations.
I think Bobbie Taylor's Tweet is also good food for thought, "You forgot the belief that the USA= the entire world, and what happens here is representative of the global condition."
