As summer begins, extreme heatwaves and droughts hit nations around the world. In Chile, the Penuelas reservoir -- once the primary water source for nearby Valparaiso -- is almost completely dry due to a 13-year drought. The reservoir once held enough water for 38,000 Olympic-size swimming pools but now only holds enough for two. “Basically, what we have is just a puddle,” said Jose Luis Murillo, general manager of the company that supplies water for Valparaiso.

In Europe, over 97% of Portugal is in “severe drought” while 35 French départements have imposed water restrictions. Spain and France are hitting highs more typical of July or August, with France about 17 degrees Celsius (63F) hotter than the seasonal average, and Spain 10 to 15 degrees (50-59F) above average. Along the French Riviera, temperatures have exceeded 35 degrees Celsius (95F) while parts of southern Spain reached 43 degrees Celsius (109F) during the country’s hottest June in at least 20 years.

Meanwhile, over 100 million Americans experienced a heat warning or advisory on Monday as a record-breaking heatwave began. Cities, including Minneapolis, Tulsa, Chicago, Charlotte, Phoenix, Memphis, St. Louis, and Denver, planned for high temperatures, with some places reaching 110 degrees Fahrenheit when factoring in the humidity.

Why This Matters

Extreme heat is a massive burden on electrical grids, water sources, and human health worldwide. The North American Electric Reliability Corporation (NERC) has already warned that this summer’s heatwaves and resulting energy demands could tax the country’s power grids, leading to blackouts and power outages for millions. Worse, extreme heat is among the most deadly natural disasters, causing more deaths in the US than hurricanes, floods, and tornadoes combined.

Even when it’s not fatal, high temperatures negatively impact our health. A new study found a correlation between rising temperatures and reduced sleep, particularly in lower-income countries with less access to air conditioning.

Heat is also a threat to national and global security and closely linked to water insecurity. The US has just declared water insecurity a national security issue for the first time in human history. Almost 50% of the world’s population is at risk of “severe water stress” by 2030, which is likely to be a key driver of climate migration.

The Long, Hot Summer Ahead

India and Pakistan’s spring heatwave could paint a picture of what’s to come. Both countries have been suffering record-breaking temperatures for months, with India’s Dehli marking its second-hottest April on record, averaging 104 degrees Fahrenheit. Added humidity makes for an even more deadly combo, and was responsible for at least 90 deaths across both countries.

In India, electricity demand has risen by at least 40% as the nation tries to keep cool, but 55% of the country’s energy needs are being met by coal.

Extreme heatwaves are increasingly common because of climate change. Instead of once every 300 years, they occur every three years.

In the US, over 100 cities could see record high temperatures this week. Much of the West and Southwest are already experiencing severe drought conditions, according to the US Drought Monitor. "This is serious heat so don’t underestimate it," the weather service in Memphis said.