September 5, 2023
Climate Shift Index Alerts
Using the Climate Shift Index, Climate Central issues alerts when there’s a notable heat event around the world that was made more likely by human-caused climate change. We also produce retrospective analyses to track the local influence of climate change.
Past Climate Shift Index alerts
The hottest 12-month stretch in recorded history (November 2022-October 2023)
Hot summer days linked to climate change in U.S. cities (U.S. summer 2023)
Carbon pollution boosted heat for billions during Earth’s hottest summer (northern hemisphere summer 2023)
About the Climate Shift Index
Climate Shift Index levels indicate how much human-caused climate change has altered the frequency of daily temperatures at a particular location. Level 1 indicates that climate change is detectable in that day’s temperature. Level 2 means that climate change made exceptionally warm temperatures in a given location at least twice as likely. Level 5 is the maximum and indicates temperatures at least 5 times more likely because of climate change.
For these analyses, forecast temperatures come from NOAA’s Global Forecast System model, and past actual temperatures come from the ERA5 dataset.