🚀 go-pugleaf

-From: u108502@beta.lanl.gov (Andrew Poutiatine)
-Subject: Re: averting doom
-Date: 6 Jan 93 15:52:12 GMT
-Organization: Los Alamos National Laboratory

->In article <JMC.92Dec29211051@SAIL.Stanford.EDU> jmc@cs.Stanford.EDU writes:
->>from a U.P. story
->>
->>	     WASHINGTON (UPI) -- Life on Earth as we know it will
->>     come to an end in 1,500 million years and the planet will
->>     look more like its dusty, volcanic sister Venus in 2,500
->>     million years, scientists said Wednesday.

-I believe the above prediction is based not on earth climate and weather
-considerations (for which I must agree predictions of more than a few days
-are not very dependable), but rather on the evolution of the sun.

-I am not an astronomer, but as I recall, theory predicts that stars of our
-sun's size go through a stage in their evolution at the end of their lives
-when they become hotter and expand.  It is this, I believe, that would
-parch the earth, killing life "as we know it."

A significant feature of the recent calculations is that as temperatures
rise, CO2 levels drop (thus regulating the surface temperature of the Earth
to some extent). Eventually CO2 drops too low to support photosynthesis,
leading to the death of multicellular organisms. The recent addition to
the model is the observation that certain plants such as corn and other
grasses do not require as much CO2 for photosynthesis as most other plants,
so there should continue to be functioning plant life for much longer than
previously expected.

John Roberts
roberts@cmr.ncsl.nist.gov