CASCADE Scientist speaks at Sonoma State University (VIDEO)

Michael Wehner spoke at Sonoma State University as part of its long running seminar series entitled “What Physicists do?”


Watch the hour and 15 minute presentation at this link

In the news: A Climate Paradox: Rising Temperatures to Bring More Droughts and Floods

Interview by Climate Nexus of CASCADE scientist Michael Wehner about the 2017 California storms on the National Geographic web pages.

Simulations Confirm Observations of 2015 India/Pakistan Heat Waves

The press release about our recent paper in the BAMS report (both CASCADE and EASM projects) quantifying the human influence on last year’s deadly heatwaves in Pakistan and India.

The report (and our 2 papers) can be downloaded from here:

The principle finding is that the human influence on these events are very large when considering the heat index, a bicubic function of temperature and relative humidity that is associated with human health and discomfort. The human influence is still there but lower when considering only temperature.


Some of the press coverage in India (all more or less the same as the PR)


Here are scatter plots of temperature and humidity for the two events to make this post less boring. The histograms show the change in distribution between the actual and counterfactual simulations of heat index.


New paper on role of attribution research in climate policy

The cover article on October 2016’s issue of Nature Climate Change discusses the possible roles of attribution research in future developments in international climate policy, and the degree to which these possible roles can be reconciled with the need for various types of justice.  CASCADE’s Dáithí Stone is a co-author.

CASCADE’s climate scientist Daithi Stone quoted in Scientific American

CASCADE’s climate scientist Daithi Stone was quoted in a recent Scientific American article about extreme event attribution.


Radio interview about 2015/6 Indian heat waves

CASCADE’s Michael Wehner on radio ecoshock (starts at 29:04)


Or click on this direct link to the audio

Performance of CAM5.1 simulations over West Africa and Southern Africa has an article today about some analysis of data produced by CASCADE.  As part of his doctoral thesis at the University of Cape Town, South Africa, Kamoru Lawal (now at the Nigerian Meteorological Agency) examined how CAM5.1 climate simulations performed under the CASCADE project manage to reproduce the major seasonal weather systems affecting West Africa and Southern Africa.  Results revealed some rather fundamental differences in the nature of predictability over both regions.  For instance, while averaging across a large number of simulations substantially improves the skill of predicting seasonal rainfall over Southern Africa, it provides little improvement over West Africa, even though the model’s skill is similar over both regions.

Benefits of mitigation for future heat extremes under RCP4.5 compared to RCP8.5

LBNL and NCAR did a joint press release on a recent paper about heat waves. The PR went fairly viral with over 800 reposts as best I can tell. Some with interesting comments… (My favorite being that Diana Ross told us all about heat waves in the 1960s. MFW.)

Click this link for the original LBNL press release:


Here is an alternative summary:

In a recent paper in the journal Climatic Change, DOE BER RGCM funded researchers Claudia Tebaldi (NCAR) and Michael Wehner (LBNL) analyzed the effects of significant reductions in future greenhouse gas emissions on short-term extreme hot and cold events. Tebaldi and Wehner applied Generalized Extreme Value (GEV) analysis techniques to the output from the large ensemble projections of the Community Earth System Model to estimate 20-year return values of daily and 3 day average maximum and minimum temperatures over the course of this century under future high (RCP8.5) and low (RCP4.5) emissions scenarios. They found that about 95% of land regions would see reductions of 1°C or more in these measures of very extreme temperatures by reducing the future increase in global mean temperature from 3.3 to 1.9oC, and 50% or more of the land areas would benefit by at least 2°C. 6% of the land area would benefit by 3°C or more in projected extreme minimum temperatures and 13% would benefit by this amount for extreme maximum temperature. The future frequency of current extremes is also greatly reduced by mitigation: by the end of the century, under the high emissions pathway more than half the land area experiences the current 20-year events every year while only between about 10 and 25% of the area is affected by such severe changes in the reduced emission scenario.

This work is joint between two larger efforts, Benefits of Reduced Anthropogenic Climate change at NCAR, which explore a wide range of such benefits and Calibrated and Systematic Characterization, Attribution and Detection of Extremes at LBNL, which is focused on extreme weather in a changing climate. See and other papers being published in the same special issue of Climatic Change.

Citation: Claudia Tebaldi and Michael Wehner (2016) Benefits of mitigation for future heat extremes under RCP4.5 compared to RCP8.5. Early online release Climatic Change. DOI:10.​1007/​s10584-016-1605-5


The difference in 20 year return values of annual maximum daily maximum temperature at the end of this century between a no policy scenario (RCP8.5) and a significant mitigation scenario (RCP4.5).


Video testimony of CASCADE scientists Daíthí Stone and Michael Wehner

Video highlights of Daíthí Stone and Michael Wehner at the National Academies of Sciences’ panel on “Extreme Weather Events and Climate Change Attribution”  on October 22, 2012.

Wehner quoted in New Scientist about the winter UK floods

CASCADE’s Michael Wehner was recently quoted in a New Scientist article about the recent UK floods. See this link: