24 January 2011
There is a common myth on climate change that goes along the lines of “How can they possibly know what the climate will do in a hundred years, when they can’t even get the forecast for tomorrow right”. This seems to be shared among a lot of TV weather people as well, and I think it is one of the main reasons that so many are skeptical of climate change. This, even in the face of an overwhelming scientific consensus.
There is no better web site for putting these myths to rest than John Cook’s Skeptical Science. I recommend different parts of that site almost daily to folks on social media and via email. John has a physics background, and all of the busted myths are based on peer reviewed science.
He recently started a project to cover about a hundred of the most popular myths, and I along with many others have participated in the process. The rebuttals to these commonly heard myths are themselves peer reviewed, and then published on Skeptical Science. The rebuttals come in a basic, intermediate, and advanced form. The result is a scientific answer to the of things you may hear at a cocktail party or God forbid from your local weather person on TV.
I just finished a basic rebuttal on myth I mentioned at the beginning of this post. You can read it on Skeptical Science here and I am posting it below as well.
Basic Rebuttal to: How can they possibly predict the climate a hundred years from now when they can’t get the forecast for the next day right!
This claim is based more on an appeal to emotion than fact. The inference is that climate predictions, decades into the future, cannot possibly be right when the weather forecast for the next day has some uncertainty.
In spite of the claim in this myth, short term weather forecasts are highly accurate and have improved dramatically over the last three decades. However, slight errors in initial conditions make a forecast beyond two weeks nearly impossible.
A change in temperature of 7º Celsius from one day to the next is barely worth noting when you are discussing weather. Seven degrees, however, make a dramatic difference when talking about climate. When the Earth’s AVERAGE temperature was 7ºC cooler than the present, ice sheets a mile thick were on top of Manhattan!
A good analogy of the difference between weather and climate is to consider a swimming pool. Imagine that the pool is being slowly filled. If someone dives in there will be waves. The waves are weather, and the average water level is the climate. A diver jumping into the pool the next day will create more waves, but the water level (aka the climate) will be higher as more water flows into the pool.
In the atmosphere the water hose is increasing greenhouse gases. They will cause the climate to warm but we will still have changing weather (waves). Climate scientists use models to forecast the average water level in the pool, not the waves. A good basic explanation of climate models is available in Climate Change- A Multidisciplinary Approach by William Burroughs.
Source: AMS Policy Statement on Weather Analysis and Forecasting. Bull. Amer Met. Soc.,79,2161-2163
*Image source: Meehl, G. A., C. Tebaldi, G. Walton, D. Easterling, and L. McDaniel (2009), Relative increase of record high maximum temperatures compared to record low minimum temperatures in the U.S., Geophys. Res. Lett., 36, L23701, doi:10.1029/2009GL040736.