Peter Pfleiderer
@klimapeter.bsky.social
Climate researcher at Leipzig University - Climate Causality & Attribution group (https://lim-climate-causality.github.io)
interested in atmospheric circulation and weather extremes | cloud lover
interested in atmospheric circulation and weather extremes | cloud lover
How the estimates of extreme event attribution are affected by aerosols depends strongly on the region and on the timing of the studied event. But in most regions, it's worth considering the aerosols in the analysis.
September 26, 2025 at 7:46 AM
How the estimates of extreme event attribution are affected by aerosols depends strongly on the region and on the timing of the studied event. But in most regions, it's worth considering the aerosols in the analysis.
The same applies for other regions and we show that considering aerosol optical depth in the probabilistic extreme event attribution approach considerably improves the estimates.
September 26, 2025 at 7:46 AM
The same applies for other regions and we show that considering aerosol optical depth in the probabilistic extreme event attribution approach considerably improves the estimates.
Over Germany, heatwaves were dampened during a period of high aerosol emissions between 1950-2000. In a standard extreme weather attribution analysis that only considers global mean temperature, this effect of the aerosols is neglected -> with implications for the estimates
September 26, 2025 at 7:46 AM
Over Germany, heatwaves were dampened during a period of high aerosol emissions between 1950-2000. In a standard extreme weather attribution analysis that only considers global mean temperature, this effect of the aerosols is neglected -> with implications for the estimates
For 2025, we again expect high hurricane activity in the Atlantic. Most seasonal forecasts (including ours) estimate an accumulated cyclone energy of more than 120 ACE.
Thanks to seasonalhurricanepredictions.bsc.es/forecast for collecting and publishing the forecasts!
Thanks to seasonalhurricanepredictions.bsc.es/forecast for collecting and publishing the forecasts!
May 7, 2025 at 7:26 AM
For 2025, we again expect high hurricane activity in the Atlantic. Most seasonal forecasts (including ours) estimate an accumulated cyclone energy of more than 120 ACE.
Thanks to seasonalhurricanepredictions.bsc.es/forecast for collecting and publishing the forecasts!
Thanks to seasonalhurricanepredictions.bsc.es/forecast for collecting and publishing the forecasts!
In our paper, we also show how this approach can be applied to other end-user relevant impacts - for example extreme fire weather, or glacier loss.
January 3, 2025 at 10:14 AM
In our paper, we also show how this approach can be applied to other end-user relevant impacts - for example extreme fire weather, or glacier loss.
For our example, different choices of critical risk levels would be possible. For instance, if one wants to be on the safe side (higher risk aversion) the acceptable cumulative CO2 emissions are substantially reduced.
January 3, 2025 at 10:13 AM
For our example, different choices of critical risk levels would be possible. For instance, if one wants to be on the safe side (higher risk aversion) the acceptable cumulative CO2 emissions are substantially reduced.
In our paper, we also show how this approach can be applied to other end-user relevant impacts - for example extreme fire weather, or glacier loss.
January 3, 2025 at 10:10 AM
In our paper, we also show how this approach can be applied to other end-user relevant impacts - for example extreme fire weather, or glacier loss.
The usefulness of reversing the impact chain relies on the ability to identify critical risk levels. A critical risk level is informed by our understanding of hazard, exposure and vulnerability but also by adaption options and limits as well as value judgements -> different choices are possible
January 3, 2025 at 10:10 AM
The usefulness of reversing the impact chain relies on the ability to identify critical risk levels. A critical risk level is informed by our understanding of hazard, exposure and vulnerability but also by adaption options and limits as well as value judgements -> different choices are possible
By reversing the impact chain, we find that this could emerge for a carbon budget between 500 and 1200 Gt of CO2 between 2020 and 2050. This carbon budget depends on our level of risk aversion. For reference: 500 Gt is what the IPCC AR6 assessed as the central remaining carbon budget for 1.5°C.
January 3, 2025 at 10:10 AM
By reversing the impact chain, we find that this could emerge for a carbon budget between 500 and 1200 Gt of CO2 between 2020 and 2050. This carbon budget depends on our level of risk aversion. For reference: 500 Gt is what the IPCC AR6 assessed as the central remaining carbon budget for 1.5°C.
Illustrative Example: An 50% increase in hot summer days might constitute a substantial health hazard for Berlin. In the forward impact chain, we would find that under a SSP1-26 scenario it is likely that the relative increase in hot days ranges between 20-110%. What do we make out of this? 🤔
January 3, 2025 at 10:10 AM
Illustrative Example: An 50% increase in hot summer days might constitute a substantial health hazard for Berlin. In the forward impact chain, we would find that under a SSP1-26 scenario it is likely that the relative increase in hot days ranges between 20-110%. What do we make out of this? 🤔
In order to make sense of this scenario information, end-users need to be experts in the ‘upstream’ climate science. Many aren’t. And, as we argue, don’t have to be. They are experts in what constitutes critical climate risks. We propose to start there with our reversal approach. How does it work?
January 3, 2025 at 10:10 AM
In order to make sense of this scenario information, end-users need to be experts in the ‘upstream’ climate science. Many aren’t. And, as we argue, don’t have to be. They are experts in what constitutes critical climate risks. We propose to start there with our reversal approach. How does it work?
When studying climate impacts we go from emission (cause) through changes in the climate system and climatic impact-drivers towards the impacts (consequences). In each step uncertainties add up leading to large uncertainties in the socio-ecological impacts most people are interested in.
January 3, 2025 at 10:10 AM
When studying climate impacts we go from emission (cause) through changes in the climate system and climatic impact-drivers towards the impacts (consequences). In each step uncertainties add up leading to large uncertainties in the socio-ecological impacts most people are interested in.
The Atlantic #hurricane season is over. It has been a highly active season with an ACE index of 162 (Accumulated Cyclone Energy). This outcome lies well within the range of our June #forecast of 133-220 ACE. Other forecasting groups expected a higher activity with an average of 211 ACE
December 2, 2024 at 11:09 AM
The Atlantic #hurricane season is over. It has been a highly active season with an ACE index of 162 (Accumulated Cyclone Energy). This outcome lies well within the range of our June #forecast of 133-220 ACE. Other forecasting groups expected a higher activity with an average of 211 ACE
Based on our seasonal #hurricane #forecast model we expect a highly active season in 2024 with an estimate of 160 ACE (accumulated cyclone energy). Other research institutes (ECMWF and CSU) forecast even higher activity
April 11, 2024 at 11:35 AM
Based on our seasonal #hurricane #forecast model we expect a highly active season in 2024 with an estimate of 160 ACE (accumulated cyclone energy). Other research institutes (ECMWF and CSU) forecast even higher activity
For precipitation, there are more diverse behaviors with some models showing a continued trend in precipitation in the period after peak warming irrespective of the cooling global mean temperatures.
January 22, 2024 at 5:57 PM
For precipitation, there are more diverse behaviors with some models showing a continued trend in precipitation in the period after peak warming irrespective of the cooling global mean temperatures.
The warming in surface air temperatures before peak warming is only partially reversed in the cooling period after peak warming for many oceanic regions. In contrast, the warming over many land regions is overcompensated in the period after peak warming.
January 22, 2024 at 5:56 PM
The warming in surface air temperatures before peak warming is only partially reversed in the cooling period after peak warming for many oceanic regions. In contrast, the warming over many land regions is overcompensated in the period after peak warming.
The rate of change in regional temperature & precipitation with respect to changes in global mean temperatures (GMST) differs between the decades before and after peak warming. Leading to differences in regional climate signals between before and after peak warming at the same global warming level.
January 22, 2024 at 5:55 PM
The rate of change in regional temperature & precipitation with respect to changes in global mean temperatures (GMST) differs between the decades before and after peak warming. Leading to differences in regional climate signals between before and after peak warming at the same global warming level.
We analyze a multi-model CMIP6 ensemble of simulations of the SSP1-19 and SSP5-34-OS scenarios.
January 22, 2024 at 5:54 PM
We analyze a multi-model CMIP6 ensemble of simulations of the SSP1-19 and SSP5-34-OS scenarios.
The Atlantic #hurricane season ends today with an accumulated cyclone energy of 144 ACE.
Once again we are satisfied with our early June seasonal #forecast of 94-181 ACE
The observed ACE is also in range of our early April we forecast (60-149 ACE)
Once again we are satisfied with our early June seasonal #forecast of 94-181 ACE
The observed ACE is also in range of our early April we forecast (60-149 ACE)
November 30, 2023 at 1:24 PM
The Atlantic #hurricane season ends today with an accumulated cyclone energy of 144 ACE.
Once again we are satisfied with our early June seasonal #forecast of 94-181 ACE
The observed ACE is also in range of our early April we forecast (60-149 ACE)
Once again we are satisfied with our early June seasonal #forecast of 94-181 ACE
The observed ACE is also in range of our early April we forecast (60-149 ACE)
Submit to our temperature overshoot #EGU24 session!
"Temperature overshoot: climate reversibility and its impacts across spatial and temporal scales"
convened by: Norman Steinert, @etheokritoff.bsky.social, Fabien Maussion, Biqing Zhu
meetingorganizer.copernicus.org/EGU24/sessio...
"Temperature overshoot: climate reversibility and its impacts across spatial and temporal scales"
convened by: Norman Steinert, @etheokritoff.bsky.social, Fabien Maussion, Biqing Zhu
meetingorganizer.copernicus.org/EGU24/sessio...
November 30, 2023 at 12:24 PM
Submit to our temperature overshoot #EGU24 session!
"Temperature overshoot: climate reversibility and its impacts across spatial and temporal scales"
convened by: Norman Steinert, @etheokritoff.bsky.social, Fabien Maussion, Biqing Zhu
meetingorganizer.copernicus.org/EGU24/sessio...
"Temperature overshoot: climate reversibility and its impacts across spatial and temporal scales"
convened by: Norman Steinert, @etheokritoff.bsky.social, Fabien Maussion, Biqing Zhu
meetingorganizer.copernicus.org/EGU24/sessio...