We discuss and comment on the role agriculture will play in the containment of the CO2 problem and address protocols for terraforming the planet Earth.
A model farm template is imagined as the central methodology. A broad range of timely science news and other topics of interest are commented on.
Saturday, January 19, 2013
The Geological Relationship Between CO2 Concentrations and Sea Level
First off, it is important to understand the actual sequence. When
the climate warms more CO2 is released into the atmosphere and the
sea level rises. The geological evidence gives us many such cycles.
We have no geological evidence of CO2 release from geological sources
and any such should be identified in some way.
What is true is that if our global heat content remains high, the ice
will melt and more CO2 will leave the ocean and enter the atmosphere.
The process can be expected top take centuries.
However, it is much more likely that we will be seeing a reversal in
which the temperature drops somewhat at least and even potentially a
lot. If we are lucky, we will have nice warm conditions lasting
centuries. That would surprise me much more.
Please note that geologically, global warming produced higher CO2 as
a lagging effect. There has been little if any evidence of the
between CO2 concentrations and sea level
reconstructions of atmospheric CO2 concentrations and sea level over
the past 40 million years, researchers based at the National
Oceanography Centre, Southampton have found that greenhouse gas
concentrations similar to the present (almost 400 parts per million)
were systematically associated with sea levels at least nine metres
above current levels.
The study determined
the 'natural equilibrium' sea level for CO2 concentrations ranging
between ice-age values of 180 parts per million and ice-free values
of more than 1,000 parts per million.
It takes many
centuries for such an equilibrium to be reached, therefore whilst the
study does not predict any sea level value for the coming century, it
does illustrate what sea level might be expected if climate were
stabilized at a certain CO2 level for several centuries.
Lead author Dr Gavin
Foster, from Ocean and Earth Science at the University of Southampton
which is based at the centre, said, "A specific case of interest
is one in which CO2 levels are kept at 400 to 450 parts per million,
because that is the requirement for the often mentioned target of a
maximum of two degrees global warming."
compiled more than two thousand pairs of CO2 and sea level data
points, spanning critical periods within the last 40 million years.
Some of these had climates warmer than present, some similar, and
some colder. They also included periods during which global
temperatures were increasing, as well as periods during which
temperatures were decreasing.
"This way, we
cover a wide variety of climate states, which puts us in the best
position to detect systematic relationships and to have the potential
for looking at future climate developments," said co-author
Professor Eelco Rohling, also from Ocean and Earth Science at the
University of Southampton.
The researchers found
that the natural relationship displays a strong rise in sea level for
CO2 increase from 180 to 400 parts per million, peaking at CO2 levels
close to present-day values, with sea level at 24 +7/-15 metres above
the present, at 68 per cent confidence limits.
relationship reflects the climatic sensitivity of the great ice
sheets of the ice ages," said Dr Foster. "It continues
above the present level because of the apparently similar sensitivity
of the Greenland and West Antarctic ice sheets, plus possibly some
coastal parts of East Antarctica."
According to the
study, sea level stays more or less constant for CO2 changes between
400 and 650 parts per million and it is only for CO2 levels above 650
parts per million that the researchers again saw a strong sea level
response for a given CO2 change.
reflects the behaviour of the large East Antarctic ice sheet in
response to climate changes at these very high CO2 levels. An
ice-free planet, with sea level 65 metres above the present, occurred
in the past when CO2 levels were around 1200 parts per million."
said, "Sea level rises to these high values will take many
centuries, or even millennia, but the implications from the
geological record are clear - for a future climate with maximum
warming of about two degrees Centigrade, that is with CO2 stabilized
at 400 to 450 parts per million, sea level is set to steadily rise
for many centuries, towards its natural equilibrium position at
around 24 +7/-15 metres, at 68 per cent confidence.
Panel on Climate Change terms, this is a likely rise of at least nine
metres above the present. Previous research indicates that such rises
above present sea level may occur at rates of roughly one metre per
Based on these
results, which document how the Earth system has operated in the
past, future stabilization of CO2 at 400-450 parts per million is
unlikely to be sufficient to avoid a significant steady long-term sea
The study is published
this week online ahead of print in Proceedings of the National
Academy of Sciences of the United States of America (PNAS manuscript
# 2012-16073R). Co-authors are Dr Gavin Foster (Ocean and Earth
Science, University of Southampton, National Oceanography Centre,
Southampton SO14 3ZH, UK) and Professor Eelco J. Rohling (Ocean and
Earth Science, University of Southampton, National Oceanography
Centre, Southampton SO14 3ZH, UK; and from 1 March 2013, Research
School of Earth Sciences, The Australian National University,