| Long-term consequences of continued carbon dioxide emission to the atmosphere |
by Ken Caldeira
Continued emissions of carbon dioxide to the
atmosphere will affect climate and ocean chemistry. These consequences can be
anticipated by consideration of basic physical principles, past climates, and
calculations. Emission of 5,000 PgC (= amount of carbon in conventional fossil-fuel
resources) over a few centuries could produce radiative forcing of climate of
about 10 W m-2 which could be expected to produce global mean
warming of ~4 to 12 °C.
Link to abstract UPDATED! Link to slides
Warming in this
range would have large biological and human consequences. It could threaten the
ice sheets and lead to a long-term sea-level rise of 70 m. Ocean pH could decrease by 0.7 units, making
the oceans more corrosive to carbonate minerals than they have been for many
millions of years. From the perspective of geology and biological evolution,
these changes would occur rapidly, overwhelming most natural processes that
would buffer CO2 changes occurring
over longer time intervals, and thus may produce changes at a rate and of a
magnitude that exceed the adaptive capacity of at least some biological
systems. To find comparable events in Earth history, we need to look back tens
of millions of years to rare catastrophic events.
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