CLIMATE EXTRMES

ClimarisQ simulates our Perception of Climate Change

Although the increase in global average temperature poses a direct extinction risk to many living species, human perception of climate change is through extreme events such as observing rainfall irregularities,(late start of the rainy season, early cessation of rainfall, and higher frequency of pockets of drought), or experiencing increasingly hot temperatures that have significant effects on agriculture and health. ClimarisQ simulates extreme climate events and their impacts on human societies using real climate models.

In ClimarisQ players try to do better than the IPCC’s intermediate scenario (RCP 4.5) and limit CO2 emissions in 2100 to [450-550] ppm to avoid the catastrophic consequences that are triggered at [800-1100] ppm. For tipping points in the climate system see here

Extreme events and climate change

The link between the development of our knowledge of climate and the prediction of extreme weather impacts remains a challenge for scientists interested in climate. The question of the link between global warming and the increase in extreme weather events recorded by meteorologists therefore has no definitive or absolute answer. It differs according to the type of event concerned. While there is little doubt about the link for some events, for others, a great deal of data is still needed before a possible causal link can be established. In ClimarisQ, the economic and societal challenges posed by the events are represented with a simulator built from IPCC models.

Extreme events in ClimarisQ

ClimarisQ includes a realistic extreme event generator (heat and cold waves, heavy rainfall, and droughts) built from data from several IPCC climate models and validated with reanalysis data (~observations) ERA5. The characteristics of extreme events implemented in ClimarisQ are the average intensity, the duration of the episodes and their frequency. These three indicators were derived under the IPCC RCP8.5 scenario which is the most pessimistic climate scenario with a radiative forcing of +8.5W/m2 and greenhouse gas emissions compatible with a “business as usual” scenario. The implementation work (internship of Soren François at LSCE under the direction of Davide Faranda) consisted of two different phases: i) characterization of extreme events in the models with respect to observations of the XX century, ii) realization of a simulator of extreme events by CO2 concentration. The realization of this generator is based on the data of the climate model selected from the analysis of the different models performed beforehand. The creation of this simulator relies on a mathematical model based on the exteme value theory allowing a rigorous description of the probability of extreme events. Also this generator uses data from 15 major metropolises on each continent (North America, South America, Europe, Africa, Asia and Oceania) which by the important concentration of people, their position of major economic poles, constitute sensitive and essential areas in the study of climate extreme events. The link between the development of our knowledge on climate and the prediction of extreme weather impacts remains a challenge for scientists interested in climate.