The Heat Will Kill You First: Life and Death on a Scorched Planet

As global temperatures rise, many species are migrating to adapt. Terrestrial animals are moving about 20 kilometers per decade, and marine species even faster. Examples include Atlantic cod shifting northward by 100 miles per decade, frogs and fungi ascending mountains, and trees in the eastern US moving north and west. However, not all species can adapt effectively; Arctic birds like thick-billed murres overheat due to their dark feathers, and Pacific salmon face lethal “migration barriers” when water temperatures rise above 70 degrees Fahrenheit, affecting their reproduction. Some species, like pine bark beetles, thrive in warmer conditions, resulting in massive infestations that destroy forests and create feedback loops that worsen climate change through increased wildfires and carbon emissions.

Historically, people have migrated rather than adapted when faced with severe environmental changes, such as during the Dust Bowl. Today, climate change is causing mass migrations globally, with droughts and floods displacing millions in regions like Southeast Asia, the African Sahel, and Pakistan. These movements have significant political ramifications, fueling xenophobia and right-wing politics. Paradoxically, many Americans are moving toward areas with high climate risks, such as Texas and Arizona, often underestimating the challenges posed by extreme heat.

The Devil’s Highway in the Sonoran Desert serves as a perilous route where extreme heat acts as a deadly barrier for migrants crossing into the US. John Orlowski of No More Deaths leaves water and supplies for migrants along this route. Orlowski explains that US Border Patrol tactics, such as “dusting” with helicopters and funneling migrants into the most dangerous areas, compound the harsh desert conditions, which have resulted in over 9,000 deaths from dehydration and heat exhaustion.

Heat is the vibration of molecules; the faster they move, the hotter the substance. Historically, theories about heat evolved from the ancient Greeks’ four elements to the caloric theory, which posited heat as an invisible fluid contained within substances. In the late 18th century, Count Rumford debunked the caloric theory by demonstrating that mechanical work could generate heat indefinitely. His experiments led to the first and second laws of thermodynamics, establishing that heat is a form of energy resulting from molecular motion.

Early climate researchers like Eunice Newton Foote and Svante Arrhenius recognized the greenhouse effect but underestimated its potential impact, often viewing a warmer climate as beneficial. In 1988, NASA scientist James Hansen testified before Congress, asserting that the greenhouse effect was already increasing the likelihood of extreme events like heat waves. Initially, the scientific consensus held that while climate change could alter the probability of such events, attributing any specific occurrence to it was impossible.

This perspective shifted with the emergence of extreme event attribution science. After witnessing severe flooding near his home in 2003, Myles Allen collaborated with Peter Stott to analyze the European heat wave of that year; they concluded that human influence had at least doubled its likelihood. This marked the birth of extreme event attribution.

Friederike Otto joined Allen’s team at the University of Oxford and became an important figure in advancing this field. She conducted studies on various extreme events, refining methods to determine the influence of climate change on their occurrence. Otto believed that it was important to deliver timely analyses to inform public understanding and policy, leading to the establishment of World Weather Attribution. Her team’s rapid assessments have linked numerous extreme events directly to human-induced climate change, providing concrete evidence of its immediate impacts.

Predicting future heat waves remains challenging due to complex atmospheric dynamics, such as changes in the jet stream influenced by disproportionate Arctic warming. Scientists acknowledge uncertainties in how hot it can get and where extreme heat waves might strike next. However, they agree that continued greenhouse gas emissions will lead to higher extremes and more frequent, severe heat waves.

Otto’s work has profound implications for legal accountability and justice. If specific extreme events can be attributed to human actions, particularly the burning of fossil fuels, it becomes possible to hold major polluters liable for damages.