This important article starts off arcane — reporting on a study of stalagmites in a Russian cave — and ends with an apocalyptic warning — we’re heating the climate 20 to 50 times faster than ever before. The study helps to resolve a disparity — the article calls it a conundrum — between computer models of past climate change and data analyses for the same period. We tend to trust data and distrust simulations but the study showed that with better data, the analysis supported the simulation. Ice ages happen because the earth’s orbit is elliptical. During ice ages, when the earth is relatively far from the sun, winters are colder, summers cooler. As the earth in its orbit gets closer to the sun, summers get warmer, winters less cold, glaciers melt and retreat, and the ice age ends. This last happened over the period 15-10,000 years ago. About 7,000 years ago, that trend stabilized and earth began a long, slow warming trend. Since then, the earth has warmed about 0.5°C. During that time, humans adopted agriculture, created civilizations, multiplied, and prospered. 
However, about 200 years ago, we began the Industrial Revolution, burning large quantities of fossil fuels, and emitting greenhouse gases which accelerated the slow warming trend. It took only 170 years to double the temperature rise of the previous 7000. In the last 40 years, thanks to growing population and prosperity, we are increasing the temperature by 20 times. If we miss the Paris Agreement target of limiting the global rise to 2°C, we could experience a heat rise rate 50 times faster than ever before. Catastrophe looms.
