WEATHER IS NOT THE SAME AS CLIMATE

A cold snap may lead some to joke that the climate is not warming. However, weather, the state of the atmosphere at a given point in time, is different from climate, the average weather over a long period of time.

Picture of Keah Schuenemann
Keah Schuenemann

“… [W]eather forecasts past five days should be taken with a grain of salt,” acknowledges Metropolitan State University of Denver’s meteorology Professor Keah Schuenemann, “but short term weather forecasts are extremely accurate and have improved dramatically.” [1] She explains:

“On the other hand, nailing the timing of weather events for a given location can be difficult. So the goal of a weather forecast is to tell you the temperature, precipitation, and cloud cover forecast for your exact position at an exact time in the near future. This is done using a variety of data from weather balloons, weather stations, and satellites that are put into a weather model.

The weather model consists of computer code that does calculations to get the forecast. The model divides the world up into blocks and the resolution, or the size of the blocks, is extremely important. …

hourly forecast
(CC) 0, NOAA, National Weather Service; www.weather.gov

And you also don’t want your storm forecast to be relegated to a low time resolution, like a day long. You’d rather have hourly or three-hourly forecasts to get a better idea of when the temperature will drop. Meteorologists analyze the results from several weather models to make the short term forecast.

Climate models … have *completely* different goals! Yes, climate models simulate weather systems and all of those useful variables that come out of a weather forecast. But the goal isn’t to tell you that the weather in … [Helena, Montana] on March 30 of the year 2050 will be a high of 0 degrees, a low of -5, and 10 centimeters of snow should fall between noon and 4:00.

The goal is to tell you that the average weather from the year 2080 to 2100 for spring over the central United States [east of the Rockies] will be an average temperature and range of such and such, this much average precipitation …. This is called the climate, the average of a bunch of weather over a long period of time.

IPCC climate model for earth warming and precipitation.
(c) IPCC AR% summary for policymakers figure SPM.07_rev1-01; www.ipcc.ch/report/ar5/syr/

To get these long-range projections, climate models are built differently than weather models. The climate is influenced by processes that happen over much longer time scales and bigger areas than weather. The climate models used in the IPCC reports, called Atmosphere-Ocean General Circulation models, include many important earth systems. They take into account cycles such as the carbon cycle. They also include feedbacks including interactions between the atmosphere, ocean, sea ice, and land that happen at a global scale.

Graphic of global climate model segments
PD, NOAA; celebrating 200years.noaa.gov/breakthroughs/climate_model/welcome.html . Click picture to enlarge.

Climate models tell us that the factors that control our everyday weather will be different in the future. So that’s how weather and climate models differ.”

Regrettably, one myth distorts the goals and capabilities of different modeling techniques in order to cast doubt on the usefulness of climate modeling. The myth is based on this misleading question: “Since computers can’t accurately predict weather two weeks from now, how can models predict what the Earth’s climate will be like in a hundred years?”

By using the emotion of disappointment in a failed weather forecast and raising the impossible expectation that models can’t predict whether or not it will snow on a certain day in a hundred years, the climate deniers have confused weather with climate in order to have you fall victim to their fallacy.

If Professor Schuenemann asked you to predict “the result of a coin flip. Heads or tails?” You would have a 50/50 chance of getting it right. If she asked you “predict the results of a million coin tosses?” You’d say about half would be heads and you’d be almost 100% correct. Her analogy demonstrates the difference between weather and climate predictions.

Asking you to apply your experience with weather forecasting (i.e., the next coin toss) to judging the validity of climate modeling (i.e., the average of a lot of coin tosses) relies on an inaccurate comparison. However, you now know, climate modeling, which compares long term average patterns over wide areas, reaches a completely different objective than weather modeling.

CLICK HERE to let us know you understand how reliable climate models indicate that burning too much fossil fuel is changing the climate, and that you will sign the petition to put the 80% renewable electricity by 2050 initiative on Montana’s 2018 general election ballot.

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