The year 2024 was just declared the hottest year on record by the National Aeronautics and Space Administration (NASA), the National Oceanic and Atmospheric Association (NOAA), and the EU’s meteorological group, Copernicus. This breaks the previous record, set only last year, as temperatures across the globe continue to spike. Most concerning of all is the amount of warming recorded: between 1.46 degrees Celsius and 1.6 degrees Celsius.
These temperatures are dangerously close to—and in the case of Copernicus, exceed— the 1.5 degree limit that the 2015 Paris Climate Agreement saw as ideal. An Intergovernmental Panel on Climate Change (IPCC) special report in 2018 further warned that 1.5 degrees of warming was a critical threshold, after which the Earth would suffer from increased risk of extreme weather and irreversible impacts on ecosystems and human societies.
Climate models predict that Earth should have experienced about 1.3 degrees of warming by now, 0.2 degrees below recorded numbers. Various explanations have been noted for this difference, from El Niño cycles to volcanic eruptions, but the impacts of each of these events has been dismissed as far too small to cause the significant 0.2 degree difference.
The most widely-accepted explanation for the gap is a decrease in cloud cover, which usually reflects incoming sunlight and keeps the planet cool. New regulations on fuel used in international shipping, as well as stricter air pollution policies in China, have led to a decrease in sulfate in the air. Sulfate attracts water droplets, creating nuclei for clouds to form around, and thus increasing cloud cover. So decreases in sulfate pollution, while important for human and animal health, may be partly to blame for the record temperatures this year.
Whatever the reason, increasing global temperatures have harmful effects on human populations and the environments we live in. Higher temperatures lead to more evaporation and more moisture in the atmosphere, thus increasing the intensity of storm surges and floods. Elevated rates of evaporation also contribute to intensified droughts, which can increase water insecurity across the globe.
Heat also has direct impacts on human health and well-being. About 489,000 heat-related deaths occur every year, and between 2000–2004 and 2017–2021, these deaths increased by about 85% (WHO). Heat exhaustion and heatstroke are only the most obvious impacts of high temperatures. Extreme heat taxes electric grids and increases the chances of blackouts, leaving people without air conditioning and even more vulnerable to the heat. A lack of proper cooling systems can also disrupt education, causing dips in test scores and sometimes even school cancellations. Farming is another cause of increasing heat, leading to decreasing crop yields, worsening livestock health, and disruptions to the storing and transporting of food.
However, not everyone is equally impacted by increasing temperatures. Black communities in cities such as Baltimore and New Orleans are disproportionately affected by disasters, largely due to a history of redlining that forced communities of color into “undesirable” neighborhoods. According to McKinsey’s Institute for Black Economic Mobility, Black communities in the Southeast are 1.8 times more likely than the overall US population living in similar areas to experience hurricanes and 1.6 times more likely to experience major flooding. Extreme heat itself also affects Black communities more—1.4 times more, to be exact. Emergency department visits due to heat-related illness increased 67% for Black people, and only 27% for white people in between 2005–2015. Rising temperatures are devastating—and as we have already passed the 1.5 degree threshold, the impacts of a warming world will only grow.
