Dr. James Hansen – Global habitability and Exxon

  • Published on July 13th, 2020

In the early 1980s scientists and the fossil fuel industry came to understand the essential characteristics of the climate system and the implications for the energy industry.  Governments decided that they preferred not to understand.  The fossil fuel industry decided to go along with the gag.

ice age climate forcings - Dr James Hansen

By Dr James Hansen

Climate is characterized by a delayed response to forcings that drive climate change, compounded by amplifying feedbacks.  The delayed response and its implications are analogous to the characteristics of the Covid-19 virus that make it capable of producing a pandemic.

With Covid-19, delays between infection, symptoms, and consequences are measured in days and weeks.  With climate, relevant time scales are decades and centuries.  This delay allows massive consequences to build up – unless there is early “anticipation.”  Early actions can minimize consequences.

Earth’s climate history allowed early quantification of climate sensitivity.  Amplifying feedbacks reign in the climate system, but they come into play slowly.  The slowness of response is both a danger and a benefit.  It provides us time to take actions before consequences are severe.

It turns out that allowable human-made forcing of the climate system, on the long run, is smaller than even most climate scientists had thought.  The allowable CO2 level is somewhere south of 350 ppm.

Most climate consequences so far are tiny.  Sea level rise so far is slight, compared to what it will be if we take no actions.  Most species are surviving, if not thriving.  The actions needed to avoid these problems will also reverse the shifting of climate zones that is beginning to cause regional problems.

It is not plausible to reach CO2 targets quickly, and it is very unhelpful to frighten young people into thinking that the problem is almost hopeless.  That is false.  The slow response of the system, in some sense, is our friend, as it gives us time to chart a successful path, if we understand the system.
More on that later.

I opened a Twitter account @DrJamesEHansen, (https://twitter.com/drjamesehansen), but for now I am focused on finishing the book.


About the Author

Dr. James Hansen directs the Program on Climate Science, Awareness and Solutions of the Earth Institute at Columbia University. The Guardian calls him "The Father of Climate Science" - his 1988 Congressional testimony on climate change helped raise broad awareness of global warming. He is often in the news advocating for a price on carbon and other forms of climate action, divesting from fossil fuels, and helping his grandchildren sue the government over their future. He is the author of "Storms of my Grandchildren".

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