One day into summer and more than 100 million people in the country are already under an excessive-heat advisory. Across the Northeast and Midwest, temperature records are toppling, emergency room visits are skyrocketing, and experts say climate change is only making matters worse, write Chelsea Harvey and Ariel Wittenberg. In fact, global warming has made the kinds of temperatures that parts of the United States are experiencing this week several times more likely to occur than what we’d see in a world without climate change, according to Climate Shift Index, a scientific tool that evaluates the influence of climate change on temperatures. The index is published by Climate Central, a Princeton, New Jersey-based organization of climate researchers. Such brutal heat so early in the summer also highlights the accelerating effects of a rapidly warming planet. Heat waves are happening more frequently, growing more intense and lasting longer as global temperatures rise — threatening human health around the world. This week, some regions in the Northeast saw their heat index, a metric combining heat and humidity, climb into the 100s. Towns in Maine, New Hampshire and Vermont experienced record-smashing highs with some areas burning hotter than South Florida. According to the climate index, temperatures in the Northeast and Midwest were made at least twice as likely by global warming, while large swaths of West Virginia, Ohio and Indiana saw temperatures that were made three or four times more likely. Despite the number of open cooling centers across the Northeast, emergency room visits for heat-related illnesses have surged, according to the Centers for Disease Control and Prevention. On Monday, just 57 out of every 100,000 emergency department visits in New England were due to heat-related illnesses. By Tuesday, that number had jumped to 469 of every 100,000. Similarly, the proportion of heat-related emergency department visits nearly doubled in the Midwest between Sunday and Tuesday. The two regions’ ER numbers were so high that the CDC’s Heat and Health Tracker website included a special icon to designate “that extremely high rates of heat-related illness were detected” in the areas. In addition to directly causing dehydration or heat stroke, extreme heat can also worsen underlying health conditions. Those that lack access to air conditioning, medical care or nutrition are at greater risk. | 
