Greenhouse gases and temperatures during the last centuries – University of Copenhagen

Greenhouse gases and temperatures during the last centuries

Over the last 100 years, the temperature at the EPICA drill site in Antarctica has risen slightly (about 0.5°C). The greenhouse gas concentrations, however, show a dramatic increase during the industrial period which is caused by the extensive human use of fossil fuels. Ice core measurements tell us that the CO2 concentration has risen from a natural interglacial level of 280-300 ppm to around 390 ppm in 2009, whereas CH4 has more than doubled from a background interglacial level of 6-700 ppb to around 1800 ppb.  

Greenhouse gas concentrations

CO2 (left) and CH4 (right) concentrations during the last 10,000 years with inserted details of the sharp increase during the last centuries. Only the last 3-60 years of data come from atmospheric measurements (red part), while all other data come from different data sets derived from analysis of ice cores. Figure modified from fig. SPM-1 of IPCC WG1-AR4.

The greenhouse gas release over the past 100 years is actually even greater than reflected in the ice core records, because much of the recently released gases have been taken up by the oceans. In the future, global temperatures are likely to continue to increase because of the strongly enhanced greenhouse effect caused by the rise in greenhouse gas concentrations. The important question is how much the temperatures will increase until equilibrium is reached. The latest IPCC report (The so-called AR4 report, that can be obtained here - opens in new window) projects a global temperature increase of 2-4°C degrees in year 2100 and even higher temperatures in the coming centuries.