For the National Climate Assessment NASA has produced a model-based prediction of eight degrees Fahrenheit for the continental US by 2100 as the most likely scenario
Story submitted by Ben Bakker
NASA scientists have created a video showing predicted dramatic heating of the continental US between now and the year 2100. The video and prediction show results of models assuming a rise in CO2 to a low of 550 ppm and a high of 800 ppm by 2100. The NASA team states that the 800 ppm value is a more likely scenario. The scenarios based upon their models lead to rises of 4 degrees and 8 degrees Fahrenheit respectively across the contiguous US. Video follows:
The team states that they calibrated 15 different models to the years as a baseline for comparison. They created two videos showing the changes in temperatures and precipitation.
The interesting part is that they chose the years 1970 to 1999 to calibrate the models. Calibrate them to what? Did they assume the co2 rise during that period was the sole factor driving temperatures across the US and calibrate the rise in temperature based on that correspondence? Did they quantify the role of pollution / aerosol reduction during that period? Changes in multi-decadal oscillations on regional climate? Changes in regional humidity? Was it a global or local model calibration? Why did they end the calibration period at 1999? Why start at 1970? With more data available and no contrasting calibrations provided this looks like a search for a high end projection. Perhaps explanations are provided in the research. Questions abound.
This is part of the upcoming National Climate Assessment Report.
Here is a description that accompanies the video:
The average temperature across the continental U.S. could be 8 degrees Fahrenheit warmer by the end of the 21st century under a climate scenario in which concentrations of the greenhouse gas carbon dioxide rise to 800 parts per million. Current concentrations stand at 400 parts per million, and are rising faster than at any time in Earth’s history.
These visualizations — which highlight computer model projections from the draft National Climate Assessment — show how average temperatures could change across the U.S. in the coming decades under two different carbon dioxide emissions scenarios.
Both scenarios project significant warming. A scenario with lower emissions, in which carbon dioxide reaches 550 parts per million by 2100, still projects average warming across the continental U.S. of 4.5 degrees Fahrenheit.
The visualizations, which combine the results from 15 global climate models, present projections of temperature changes from 2000 to 2100 compared to the historical average from 1970 -1999. They were produced by the Scientific Visualization Studio at NASA’s Goddard Space Flight Center, Greenbelt, Md., in collaboration with NOAA’s National Climatic Data Center and the Cooperative Institute for Climate and Satellites, both in Asheville, N.C.
The visualizations show the temperature changes as a 30-year running average. The date seen in the bottom-right corner is the mid-point of the 30-year average being shown.
“These visualizations communicate a picture of the impacts of climate change in a way that words do not,” says Allison Leidner, Ph.D., a scientist who coordinates NASA’s involvement in the National Climate Assessment “When I look at the scenarios for future temperature and precipitation, I really see how dramatically our nation’s climate could change.”
To learn more about the National Climate Assessment, due out in 2014, visit here: http://www.globalchange.gov/what-we-d…