This month marks the 80th anniversary of the first, and so far only, use of atomic weapons in war. The United States dropped an atomic bomb on Hiroshima, Japan, on August 6, 1945. A second bomb was dropped three days later on Nagasaki. The death toll is estimated in the hundreds of thousands. The attacks prompted Japan’s surrender and ended World War II. They also kick-started an arms race based on deterrence: If multiple countries have the bomb, they should be less likely to use it, or risk global devastation.
The threat of nuclear war has flared and faded in the decades since, but it became much more salient in June, when the United States bombed Iranian facilities devoted to developing nuclear weapons. Iran has a stockpile of enriched uranium but does not yet have nuclear weapons. But the increased hostilities raise the question of whether the conflict will expand to include countries beyond the United States that do have them — and how the United States could protect itself.
The current U.S. nuclear defense system was designed to fend off a small-scale attack by a country with limited offensive capabilities, such as North Korea. In May, President Donald Trump unveiled plans for his “Golden Dome” concept. It is imagined as a major upgrade, able to block multiple kinds of strikes from a well-armed foe such as China or Russia. Missile defense technology has advanced over the years. But as Science News’ senior physics writer Emily Conover reports, the laws of physics make a successful interception of even one missile extremely challenging.
As if the threat of nuclear warfare wasn’t enough to worry about, this summer has also brought more record-smashing heat. Critics of human-caused climate change sometimes note that the planet has gone through cycles when it was much, much hotter than it is now, and thus argue that the current upward trend is not a threat. The planet has indeed endured multiple wild temperature swings.
But while the planet has survived those changes, many of its inhabitants did not. Scientists are closely examining Earth’s chaotic history to get a clearer sense of when things will get too hot for humans in the future, freelance writer Elise Cutts reports. There’s no question that the rising levels of human-generated carbon in the atmosphere are increasing the odds that things will get too toasty much sooner than many of us would like.