Year by year, millimeter by millimeter, the seas are rising. Fed by melting glaciers and ice sheets, and swollen by thermal expansion of water as the planet warms, the world’s oceans now on average are about eight inches higher than a century ago. And this sea change is only getting started.
A new look at the “vital signs” of Earth’s climate reveals a stark picture of declining health. As global temperatures rise, so do sea level and the amount of heat trapped in the ocean’s upper layers. Meanwhile, mountain glaciers and Arctic sea ice are melting away beneath an atmosphere where concentrations of three key planet-warming greenhouse gases continue to rise.
“Data show that the climate is changing more rapidly now than it has at any time in the historical record,” says Thomas Karl, director of the National Oceanic and Atmospheric Administration’s (NOAA’s) National Climatic Data Center in Asheville, North Carolina. “The numbers speak for themselves.”
While often portrayed as an unsettled debate, the reality is that 97% of scientists agree global warming is happening and humans are to blame.
Top scientific organizations like the American Association for the Advancement of Science, the American Medical Association and the World Health Organization, along with hundreds of others around the world, all endorse this position.