“But will we choose a different road? Your guess is as good as any scientist’s. Human decisions remain the main source of uncertainty in climate change, not the physical response of the climate itself. The confidence level of the physical predictions for many years has exceeded the certainty we need for other big choices, such as when we decide economic policies or court cases. But predicting the human component of reducing carbon emissions depends on politics and social psychology, which constantly surprise the best experts.
We’ve already blown through a lot of irreversible changes without taking effective action. Carbon dioxide that we emit stays in the atmosphere permanently, in terms meaningful to human time horizons. The atmospheric concentration of CO2 has gone from 280 parts per million before the industrial revolution to about 400 parts per million [in 2016], and it increases at 2 parts per million per year. We’re seeing many damaging impacts, with melting glaciers and permafrost, disappearing sea ice, increasing droughts, heat waves and fires, stronger storms, accelerated sea level rise, altered growing seasons and habitat ranges, and so on. Impacts lag emissions, so more severe changes are already inevitable.
But on the hopeful side, every major carbon-emitting nation made commitments to reduce emission at a Paris summit in December 2015, the first time that had happened. It wasn’t enough, but for the first time the whole world pulled in the same direction.
Carbon reduction depends on peace between nations. And changing climate could be a great impetus to war. The physical sciences have found many feedback loops by which warming begets more warming, but the social science connection of carbon and conflict could be the most powerful of all.”
–Charles Wohlforth, lifetime Alaska resident and LA Times Award winning science and environment writer, and Dr. Amanda Hendrix, 20-year planetary scientist, in their 2016 book projecting possible futures for humanity
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