Ben Santer writes: I’ve been a mountaineer for most of my life. Mountains are in my blood. In my early 20s, while climbing in France, I fell in a crevasse on the Milieu Glacier, at the start of the normal route on the Aiguille d’Argentière. Remarkably, I was unhurt. From the grip of the banded ice, I saw a thin slit of blue sky 120 feet above me. The math was simple: Climb 120 feet. If I reached that slit of blue sky, I would live. If I didn’t, I’d freeze to death in the cold and dark.

Now, over 40 years later, it feels like I’m back in a different kind of darkness — the darkness of the Trump administration’s scientific ignorance. This is just as real as the darkness of the Milieu Glacier’s interior, and just as life-threatening. This time, I’m not alone. The consequences of this ignorance affect every person on the planet.

Imagine, if you will, that you spend your entire professional life trying to do one thing to the best of your ability. In my case, that one thing is to study the nature and causes of climate change. You put in a long apprenticeship. You spend years learning about the climate system, computer models of climate and climate observations. You start filling a tool kit with the statistical and mathematical methods you’ll need for analyzing complex data sets. You are taught how electrical engineers detect signals embedded in noisy data. You apply those engineering insights to the detection of a human-caused warming signal buried in the natural “noise” of Earth’s climate. Eventually, you learn that human activities are warming Earth’s surface, and you publish this finding in peer-reviewed literature. [Continue reading…]