A new study by Carnegie’s Ken Caldeira and Nathan Myhrvold of Intellectual ventures shows the pattern of climate change to be a rapid increase within the first decade followed by a very slow increase. Their work, published in Environmental Research Letters, shows about half of the warming occurs within the first decade, but a quarter of the warming occurs more than a century after the increase.
This study reflects results from the world’s leading climate models. Caldeira and Myhrvold used 20 different climate models to analyze more than 50 different climate scenarios for the Climate Model Intercomparison Project, Phase 5 (CMIP5). They found people generally agreed upon the pace of climate change. Following an instantaneous increase in greenhouse gas emissions, climate change begins a slow increase.
There are however, disagreements among models. The maximum percent of warming within the first decade is shown to be 38 percent in one model, 61 percent in another model, and a generous amount of 86 percent in another model.
The amount of warming is also under question with the most serious case being twice as much as the least sensitive model predicts. Finally, there are differing opinions on the pace of warming. Some models predict that a 2-degree increase would take less than a decade, while other models say it would take over a century.
Ken Caldeira reminds us that while there are uncertain aspects to climate change, the overall situation remains the same. “If we continue increasing atmospheric CO2 concentrations with emissions from the burning of coal, oil, and gas, the Earth will continue to get hotter. If we want the Earth to stop getting hotter, we have to stop building things with smokestacks and tailpipes that emit CO2 into the atmosphere,” said Caldeira.