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New research from Climate Central indicates that climate change accounted for 27% of the rate of heat-related emergency room visits in the U.S. during the warm seasons from 2018 to 2025. The study found that all U.S. regions experienced increased visit rates due to climate change, with the highest rates occurring in southern and western states. A notable peak occurred during the June 2021 northwestern U.S. heat wave, where daily visit rates were approximately 50 times higher than the regional average, with 27% of that rate attributed to climate change.

The report finds that August 2026 saw widespread above-average temperatures across the U.S., with an average anomaly of 1.6°F across 192 cities. The Southwest was the hottest region, and 39 cities recorded one of their top-five hottest Augusts on record. Long-term trends show August warming since 1970 in 187 of the 192 analyzed locations, with Reno, Nevada, seeing the largest increase.

The report finds that record-breaking sea surface temperatures in July 2026 across European coasts were driven by human-induced climate change, with some regions experiencing warming that substantially exceeds global averages. These extreme temperatures have triggered marine heatwaves, species range shifts, and increased risks to human health and coastal infrastructure. The analysis indicates that such events would have been virtually impossible in a pre-industrial climate and will continue to intensify as global warming progresses.

The 2026 floods in Upper Assam, which affected over 500,000 people and caused at least 99 deaths, were driven by high exposure and structural vulnerability rather than climate-driven rainfall increases. Analysis shows the rainfall events had return periods of less than two years and that human-induced warming of 1.4°C did not materially alter their likelihood or intensity. The study highlights that unplanned urbanization, deforestation, and colonial land policies have increased vulnerability, while reliance on rigid embankments has proven insufficient for adaptation.

Analysis of 243 to 247 major U.S. cities reveals that 95% have seen an increase in unusually warm summer nights since 1970, with an average increase of 24 nights per summer. Using the Climate Shift Index (CSI), the report finds that human-caused climate change now strongly influences an average of 27 warm summer nights per year, compared to just one in the 1970s. The most severe impacts are concentrated in Florida and Puerto Rico, where some cities experience over two months of climate-driven warm nights annually. These trends exacerbate heat stress, disrupt sleep, and increase energy demand for air conditioning, disproportionately affecting vulnerable populations and those in urban heat islands.

In July 2026, the United States experienced widespread above-average temperatures, with an average anomaly of 1.5°F across 192 cities. The Northern Rockies and Plains were the warmest region, exceeding normals by more than 4.0°F. Long-term data indicates that 185 of the 192 analyzed cities have warmed since 1970, with Reno, Nevada, showing the most significant increase. Climate attribution analysis using the Climate Shift Index (CSI) showed that San Juan, Puerto Rico, had 31 days where temperatures were at least two times more likely due to climate change.

July 2026 was tied for the warmest July on record globally and was the all-time warmest July for the contiguous U.S. This extreme heat, driven by human-caused climate change and a strengthening El Niño, has led to a significant increase in cooling degree days—a proxy for energy demand—across most major U.S. cities. The report also details widespread drought affecting at least 70% of the contiguous U.S. and record-low sea-ice extents in both the Arctic and Antarctic.

Research by the Union of Concerned Scientists and University of California, Merced, indicates that emissions from the 'Carbon Majors'—the 122 largest industrial carbon producers—are responsible for approximately half of the climate-driven reductions in snowpack and streamflow, and increases in irrigation demand across the western United States. The analysis highlights specific 'hot spots' in California and the Pacific Northwest, noting that these emissions contributed to a 15% reduction in April snowpack and a 6.1% decrease in warm season streamflow. In California's Central Valley, 10% of observed groundwater loss is attributed to these companies. The document argues that the fossil fuel industry should be held financially accountable for these damages, as local governments and vulnerable communities currently bear the economic costs of adaptation and infrastructure failure.

The June 2026 heatwave in Western Europe is the most severe ever recorded for the region, with temperatures 5–12°C above seasonal averages. Analysis shows that such an event would have been virtually impossible in 1976 and significantly rarer in 2003, indicating that extreme heat is increasing rapidly due to global warming. The event caused widespread disruption to transport, energy systems, and health services, with 45% of European cities breaking indoor Wet Bulb Globe Temperature (WBGT) thresholds.

Since the 1970s, the global average number of dangerous humid heat days—defined as those with a maximum wet-bulb temperature of 25°C or higher—has more than doubled, rising from 10 to 23 days per year. Climate Central's analysis indicates that human-caused climate change is now the primary driver of this trend, accounting for 64% of all such days since 1970 and 83% of the 23 dangerous days recorded in 2025. The most significant increases are observed in tropical humid regions, including Southeast Asia, coastal West Africa, and tropical South America, though increases are also noted in drier areas like the Arabian Peninsula and the southwestern United States.

Climate Central analysis shows that 14 of the 16 host stadiums for the 2026 World Cup are experiencing more extremely hot days during the June-July tournament period than in 1970. Human-caused climate change is responsible for an average of 49% of these extreme heat days across all stadiums, with the highest impact seen in Miami and Mexico City. In 10 repeat host cities, the frequency of extremely hot days has tripled on average since they last hosted the tournament.

The report finds that anthropogenic climate change has significantly increased the probability of dangerous humid heat during the 2026 FIFA World Cup compared to 1994. Using Wet Bulb Globe Temperature (WBGT) as a metric, the analysis indicates that more games are expected to exceed the 26C and 28C thresholds recommended by FIFPRO for cooling breaks and postponement, respectively. While air-conditioned stadiums may mitigate risks for players, spectators at outdoor events remain vulnerable. The study concludes that without substantial adaptation and rapid mitigation of fossil fuel use, hosting summer tournaments in the northern hemisphere will become increasingly hazardous.

In April 2026, the United States experienced an average temperature anomaly of 3.4°F across 192 cities, with the Ohio Valley being the warmest region. The report highlights that 183 of the analyzed cities have shown long-term warming trends since 1970, with Reno, Nevada, seeing the greatest increase. Climate attribution analysis indicates that in San Juan, Puerto Rico, temperatures on 19 days in April were at least two times more likely due to climate change.

In May 2026, the United States experienced slightly below-average temperatures overall, with an average anomaly of -0.2°F across 192 cities. Despite this, the western U.S. saw above-average temperatures, and the Northern Rockies and Plains region was the warmest, averaging more than 1.6°F above normal. Long-term data indicates that 185 of the 192 analyzed cities have warmed since 1970, with Reno, Nevada, showing the greatest increase at 7.5°F. Climate attribution analysis shows that San Juan, Puerto Rico, had the highest number of days (28) where temperatures were at least two times more likely due to climate change (CSI level 2 or higher).

A severe marine heat wave is impacting the northeast Pacific Ocean, with temperatures 2-5°F above normal and peak anomalies reaching 11°F. The event is strongly influenced by human-caused warming, which has increased the heat wave's footprint and duration.

In March 2026, the United States experienced unprecedented warmth with an average temperature anomaly of 5.8°F across 192 cities. The Southwest was the warmest region, with temperatures more than 10.4°F above normal, and Phoenix recorded the highest individual city anomaly at 12.5°F. Long-term trends show that 188 of the 192 analyzed cities have warmed since 1970, with Wheeling, West Virginia, seeing the greatest increase of 11.7°F. Climate attribution analysis using the Climate Shift Index (CSI) indicates that in Flagstaff, Arizona, temperatures on 28 days in March were made at least two times more likely due to climate change.

April 2026 was the fourth-warmest month globally on record, with the contiguous U.S. experiencing its third-warmest April. The report highlights severe drought in the Southeast U.S., record-low Western snowpack, and a persistent marine heat wave off the coasts of California and Mexico. Using the Climate Shift Index (CSI), the analysis attributes springtime warming trends in 98% of analyzed U.S. cities to human-caused climate change, with exceptional warmth noted in Honolulu and San Juan. Forecasts indicate a high probability of a strong El Niño developing later in 2026, potentially driving global temperature anomalies above 1.8°C relative to pre-industrial levels by early 2027.

Between December 2025 and February 2026, human-caused climate change significantly influenced global temperatures, with more than one in six people daily experiencing temperatures at least twice as likely due to climate change. In the United States, a sharp divide occurred: western states saw record-breaking warmth, with nine states experiencing their warmest December-February on record and Casper, Wyoming, recording the highest temperature anomaly globally among 960 analyzed cities. Conversely, the eastern U.S. faced below-average temperatures and cold snaps that the Climate Shift Index (CSI) indicates were made less likely by climate change. The record warmth in the west has led to low snowpack in Oregon, Colorado, and Utah, threatening water supplies and increasing wildfire risks.

Between December 2025 and February 2026, climate change significantly boosted global temperatures, with over one in six people experiencing strong climate influence daily. Nearly 228 million people faced 30 or more risky heat days added by climate change, with 81% of these individuals residing in Africa. The analysis highlights that in 45 countries, all risky heat days during this period were driven by climate change, and 124 countries saw the average person experience at least 30 days of strong climate influence (CSI level 2 or higher).

In February 2026, the United States experienced an average temperature anomaly of 2.1°F across 192 cities. While the Northeast was the coldest region with an average anomaly of -3.4°F, the Northern Rockies and Plains were the warmest, exceeding normal temperatures by more than 8.4°F. Long-term data indicates that 173 of the 192 analyzed cities have warmed since 1970, with Albany, Georgia, showing the greatest increase at 8.4°F. Climate attribution analysis using the Climate Shift Index (CSI) found that San Juan, Puerto Rico, had 16 days where temperatures were at least five times more likely due to climate change.