WP 4: Climate Sensitivity

Work Package 4: Earth System Sensitivity
The IPCC defines Climate Sensitivity as the equilibrium change in global mean surface temperature due to a doubling in atmospheric carbon dioxide concentration. In other words: How much warmer will the earth become when concentrations of carbon dioxide in the atmosphere double? The IPCC has an answer: between 2.1 and 4.4 °C, but with NESSC, we aim for a much smaller range.

To calculate climate change in the near future, we need to calculate today’s climate sensitivity first. To do so, we need to determine Earth System Sensitivity from so called fast feedbacks and tweak the results with data from the distant past. Fast feedbacks involve processes associated with clouds, snow, sea ice and water vapour, and typically have timescales of up to a few decades—hence the name. But, as mentioned before, the sensitivity of our current and future climate doesn’t only depend on those fast feedbacks. We need to correct it with the effects of the slow feedbacks from up to one hundred million years ago.

In Work Package 4 we show that the climate of certain periods in de distant past can determine today’s sensitivity of earth’s climate. In Work Package 5 we use these results to search for tipping points in the past and predict them in the near future.

Contact person: prof. dr. Appy Sluijs