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Studying past climates can help scientists predict how the planet will change in the future. Using historical data, scientists at the University of Bristol, have developed a new model of climate change they believe is more accurate than previous estimates.
Leaving certain data out of climate models, researchers discovered, has led to exceedingly modest estimates of the effect of carbon emissions on the planet.Dan Lunt, who led the study, compared current climate model results to reconstructions based on the earth's temperature and atmospheric carbon dioxide levels three million years ago. He explained:
We found that, given the concentrations of carbon dioxide prevailing three million years ago, the model originally predicted a significantly smaller temperature increase than that indicated by the reconstructions. This led us to review what was missing from the [current] model.
Factors with long timescale variables, like melting sea-ice and changes in vegetation, had a significant impact when added to climate models. When these variables were added, the models showed a planet that is significantly more sensitive to carbon emissions.
Most models, researchers explained, including the ones used by the IPCC, do not fully-incorporate these long timescale variables. As a result, the impact carbon emissions have on the planet's temperature has been underestimated by between 30 and 50 percent.
Alan Haywood, one of the study's co-authors, explained that, "if we want to avoid dangerous climate change, this high sensitivity of the Earth to carbon dioxide should be taken into account when defining targets for the long-term stabilization of atmospheric greenhouse-gas concentrations."
Read more about climate models:
Animated Climate Model By Geophysical Fluid Dynamics Laboratory
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A Breakthrough in Climate Modeling Shows Past Temperatures and Future Changes