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Climate Central analyzed cooling degree days (CDD) across 243 U.S. locations, finding that 95% experienced increased cooling demand during the back-to-school period (July 17 to September 8) since 1970. Over the last decade, human-caused climate change increased this demand by approximately 34%. The report highlights that extreme heat negatively impacts children's learning and health, while many U.S. schools lack the necessary HVAC infrastructure to adapt to these rising temperatures.

The report finds that July 2024 temperatures were elevated in the eastern and western thirds of the United States, with the West Coast showing particularly high anomalies. Using the Climate Shift Index (CSI), the analysis identifies the Southwest as having the strongest climate signal, with cities averaging at least 14 days where temperatures were at least three times more likely due to climate change. Specific cities like Spokane, Washington, and Reno, Nevada, showed significant temperature anomalies and long-term warming trends since 1970.

Climate Central reports that 89% of 242 analyzed U.S. locations have seen an increase in annual 'warning days' (heat index 80°F to 94°F) since 1979, with the most significant rises in the Ohio Valley and Upper Midwest. Between 1992 and 2022, 986 U.S. workers died from heat exposure, and from 1980 to 2016, an average of 421 million work hours were lost annually, costing $14 billion. The document highlights a lack of comprehensive federal heat standards, noting that only five states have such protections, while some states like Florida and Texas prohibit local municipalities from enacting their own heat safety laws.

Climate Central analysis shows that 88% of 242 analyzed U.S. cities have seen an increase in extremely hot days since 1970, posing significant risks of heat-related illness and death for student athletes, particularly youth and teens.

Climate Central analyzed the urban heat island (UHI) index across 65 major U.S. cities, finding that 68% of the 50 million residents in these cities live in areas where the built environment increases temperatures by 8°F or more. The study identifies albedo, green space, and population density as the primary drivers of this effect. It also highlights a link between historical redlining and current heat disparities, noting that in 84% of 179 analyzed cities, historically redlined areas experience hotter summers than non-redlined areas.

The report finds that June 2024 was historically hot across the United States, with climate change making temperatures 2.3 times more likely on average. The Southwest experienced the most extreme anomalies, with Nevada's temperatures being 8.2 times more likely due to climate change and the region seeing an average of 4.2 additional days above 90°F. Analysis of 191 ACIS stations showed that 12 experienced their hottest Junes on record, and 168 stations had at least one day where temperatures were at least twice as likely due to climate change.

Between June 16 and 24, 2024, approximately 4.97 billion people—over 60% of the global population—were exposed to extreme heat that was at least three times more likely to occur due to climate change. The analysis, using the Climate Shift Index (CSI), highlights severe impacts across India, China, Indonesia, Nigeria, Brazil, and the United States, as well as lethal heat waves in Saudi Arabia, Mexico, and Egypt.

Climate change is increasing the frequency of nighttime temperatures exceeding 18°C, 20°C, and 25°C, which impairs human sleep and increases health risks. Between 2018 and 2023, the average person globally experienced 4.8 additional days per year above 20°C and 11.5 additional days above 25°C due to climate change. The report highlights severe impacts in specific regions, such as California in the U.S. and West Bengal and Assam in India, where the number of added hot nights is highest.

From June 18-20, 2024, a major to extreme heat event is forecast for the eastern half of the U.S., affecting over 25 million people. The event is characterized by record-level high temperatures in major cities and elevated nighttime temperatures. Climate Central's Climate Shift Index (CSI) indicates that human-caused climate change has made this heat at least four times more likely in several states, including West Virginia, Ohio, and Indiana.

The Southwest United States experienced an extreme heat event from June 6 to June 13, 2024, with human-caused climate change making high temperatures at least five times more likely. The event caused record-setting temperatures in cities like Phoenix and Las Vegas, led to numerous hospitalizations for heat exhaustion, and contributed to wildfires in California.

From June 11-13, 2024, over 290 million people in Northern Africa, the Mediterranean, and the Middle East are forecast to experience extreme heat made at least five times more likely due to human-caused climate change. Maximum temperatures of 40°C or higher are expected in several countries, including Saudi Arabia, Iraq, Syria, and Egypt. The document highlights risks including wildfires in Greece, damage to Bulgaria's rose oil production, and increased vulnerability for refugees in Libya, Tunisia, and Algeria.

Between March and May 2024, global temperature records were broken for three consecutive months. Using the Climate Shift Index (CSI), the analysis found that approximately one in four people worldwide experienced temperatures at least three times more likely due to climate change (CSI level 3+) daily. Exposure peaked on April 6, 2024, with 2.7 billion people affected. The most severe impacts were concentrated in Africa, Southeast Asia, Central America, and South America, with 44% of Africa's population experiencing the most extreme attributable heat (CSI level 5 for 60+ days). The report also highlights a strong regional contrast in the U.S., where coastal areas and islands showed higher CSI signals despite lower temperature anomalies compared to the Upper Midwest.

Using the Climate Shift Index (CSI), Climate Central found that human-caused climate change significantly boosted spring warmth in 2024, affecting 300 million people in the U.S. and approximately one in four people globally. The strongest influence was observed in coastal and island regions, such as Puerto Rico and Florida, while areas with the highest temperature anomalies, like the Upper Midwest, showed lower CSI levels due to higher historical temperature variance.

The report finds that human-induced climate change significantly increased the frequency, intensity, and duration of extreme heat globally from May 2023 to May 2024. Using the Climate Shift Index (CSI), the study determined that 6.3 billion people experienced at least 31 days of extreme heat made at least twice as likely by climate change. It identifies 76 extreme heat waves across 90 countries and highlights critical gaps in impact reporting, particularly in developing regions. The authors advocate for City Heat Action Plans and systemic adaptations to prevent heat-related fatalities.

Climate Central analyzed annual coastal flood risks for 23 U.S. cities using Risk Finder and the Coastal Risk Screening Tool. The analysis highlights the impact of human-caused sea level rise, noting it contributed 13% of Hurricane Sandy's damages in the Northeast. For specific cities, the report identifies annual likelihoods of flooding at various levels above Mean Higher High Water (MHHW), such as a 20% likelihood for Norfolk at MHHW +4 feet. The document also notes that atmospheric warming is increasing the proportion of Category 4 and 5 hurricanes globally and may lead to more frequent back-to-back storms and rapid intensification.

Analysis of 241 U.S. locations from 1970 to 2023 shows that 95% have experienced warming average summer temperatures, with an average increase of 2.5°F. The Northwest, Southwest, and South regions saw the most significant heating. Additionally, 58% of analyzed locations now experience at least 14 more above-normal summer days than in 1970. The document also highlights the health risks of extreme heat, particularly for vulnerable populations and those affected by urban heat islands, and provides a directory of monitoring tools and hurricane season resources.

Climate Central analysis indicates that human-caused climate change increased the likelihood of an intense heat event in western and northwestern India from May 18-20, 2024. Forecasts predict daily high temperatures 3°C to over 6°C above average, with some areas exceeding 47°C and nighttime lows remaining above 34°C. Approximately 543 million people in India are expected to experience at least one day with a Climate Shift Index (CSI) level of 3 or higher during this period.

An analysis of 476 weather stations from 1973 to 2023 shows that fire weather seasons are lengthening and intensifying across the contiguous United States, with the most significant increases occurring in the West. While the East has seen more modest increases, both regions are experiencing a notable rise in fire weather days during the spring. The Southwest has seen the most dramatic growth, with some areas experiencing fire weather twice as often as they did 50 years ago.

Florida is expected to experience dangerous early-season heat from May 14-16, 2024, with temperatures exceeding 90°F and heat index values between 100°F and 105°F. Human-caused climate change has made these conditions more than five times more likely, as indicated by a Climate Shift Index (CSI) level of 5 in Central and Southern Florida. Approximately 17 million people are expected to experience at least one day of CSI level 5 heat. The event is characterized by high humidity and overnight lows 5°-10°F above average, increasing the risk of heat-related illnesses and mortality, particularly for those without effective cooling.

Climate change is increasing the intensity of extreme precipitation across the U.S., with the Northeast and Midwest seeing the largest increases since 1958. Under 2°C of global warming, 85% of U.S. counties are projected to experience a 10% or higher increase in precipitation on the heaviest 1% of days. This intensification contributes to flash flooding and landslides, disproportionately affecting racial minorities and those in mobile homes, particularly in the South and rural areas. Between 1988 and 2021, warming-induced rainfall intensification caused an estimated $84 billion in inland flood damages.