The Eiffel Tower lights up with the slogan "Action Now" on Dec. 6, 2015, in connection with the United Nations Climate Change Conference in Paris. (Michel Euler/AP)

Kudos to Courtland Milloy and many others sounding the alarm on climate change [“Climate change demands leadership — it can’t wait,” Metro, Aug. 14]. The hidden problem with climate change is that it doesn’t proceed at a constant pace; instead, it is accelerating because of numerous positive feedback loops. One simple example: When white arctic ice, which reflects most sunlight back into space, melts and exposes brown earth, that earth absorbs sunlight and melts the ice even faster — which exposes more earth, which melts still more ice. That feedback loop spirals faster and faster.

We are very close to a tipping point at which man-made climate change is happening so fast that there will no longer be anything we can do to stop that runaway train. If we haven’t already hit that tipping point, it is frighteningly close — a half-dozen years or so.

Take a look at the May/June issue of the MIT Technology Review for a hard-nosed look at the reality of climate change. We’re either going to act right now, with everything we’ve got, or human life is finished on this planet. To quote from that issue: “And the strong possibility that our great-grandchildren may be the last generation of humans ever to live on planet Earth.” We’re in big trouble, and it’s worsening rapidly, but our politicians think campaign contributions from big business are more important.

George Wedberg, Rockville

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