Fair Plan 7: Earth’s Climate Future = Humanity’s Choice

Abstract

Earth’s climate future is in the hands of humanity. If emissions of greenhouse gases remain unabated, Earth’s climate will return to the climate of the Late Eocene, 35 million years ago, when sea level was 73 meters (240 feet) higher than today. Should that occur, many coastal cities around the world would be inundated. Moreover the Global Warming of this unabated Reference case will be comparable to the Global Warming from the Last Glacial Maximum 21,000 years ago to the beginning of the Holocene interglacial climate 11,000 years ago. However, this human-caused Global Warming would occur 50 times faster than that caused by nature. Alternatively, humanity can mitigate greenhouse-gas emissions to keep Global Warming below the 2˚C maximum adopted by the United Nations Framework Convention on Climate Change “to prevent dangerous anthropogenic interference with the climate system”. This mitigation can either be done rapidly, as in the “80/50” Plan to reduce greenhouse-gas emissions 80% by 2050, or much more slowly, from 2020 to 2100, as in the Fair Plan to Safeguard Earth’s Climate. The Fair Plan is a compromise between doing nothing, as in the Reference case, and rapidly reducing greenhouse-gas emissions, as in the 80/50 Plan. Regardless of the Plan chosen to reduce greenhouse-gas emissions to keep Global Warming below the UNFCCC limit of 2˚C (3.6˚F), it should not be tantamount to our saying to one of our planetary spacecraft, Bon Voyage, call us when you get to your planetary destination. Rather, as with our spacecraft, the chosen climate-change policy should be monitored throughout the 21st century and Midcourse Corrections made thereto as needed to keep our “Climate Spacecraft” on track to achieve its “Climate Target”.