What We Observe Now

Direct measurements show unmistakable trends. The twenty warmest years on record have all occurred since 1998. Global sea levels have risen about twenty centimeters since 1900, and the rate is accelerating. Arctic sea ice extent has declined by roughly thirteen percent per decade since satellite measurements began in 1979.

Ocean temperatures are rising to depths of thousands of meters. This matters enormously because the oceans have absorbed roughly ninety percent of the excess heat trapped by greenhouse gases. Without that buffer, atmospheric warming would be far higher.