Haverd, V., Smith, B.,
Canadell, J.G., Cuntz, M.,
Mikaloff-Fletcher, S.,
Farquhar, G., Woodgate, W.,
Briggs, P.R. and Trudinger, C.M.
2020
Higher than expected
CO2 fertilization
inferred from leaf
to global observations.
Global Change Biology,
https://doi.org/10.1111/gcb.14950.
NOTE:
CO2 is the
staff of life
on our planet --
only a science denier
would deny that fact,
and try to hide
the huge benefit
of extra CO2
in the air.
NASA satellites
have measured
the 'greening'
of our planet,
but they try
to obscure
one cause.
People with science
degrees who work
for governments,
or receive some
government grants,
MUST demonize CO2
to get their money
-- they must "believe"
what they are paid
to believe.
Just like scientists
working for cigarette
companies were
paid to believe
that smoking
was safe !
It's okay to ASSUME
CO2 causes mild,
harmless global
warming, based on
lab experiments.
But the usual claim,
is dangerous CO2
warming, which is
NOT supported
by any real science,
or by the past 325 years
of mild global warming.
Only a science denier
would ignore the
thousands of studies
proving that more CO2
in the atmosphere
accelerates plant growth,
and allows the plants
to use less water too.
Summaries of
dozens of studies
have been published
here, on this blog.
The fertilizer effect
of CO2 is why so many
greenhouse owners
pay for, and use,
CO2 enrichment
systems, to double
or triple the CO2 level
inside their greenhouses,
SUMMARY:
Current CMIP5
climate models
grossly underestimate
the future land sink
( mainly plants absorbing
CO2 ), by 129%, with the
low CO2 emissions scenario
( RCP2.6 )
These models
fail to correctly
account for the
positive impacts
of CO2 fertilization.
As shown
in the charts below,
global gross
primary production
( GPP )
increased 35%
since 1900,
primarily driven by the
aerial fertilization effect
of atmospheric CO2.
More CO2
in the atmosphere
increases plant productivity,
enhances plant water use
efficiency, and reduces
resource limitations and
environmental stresses.
Haverd et al. report
that atmospheric CO2
increases were
directly or indirectly
responsible
for over 85%
of the increase
in GPP
The Haverd et al. (2020)
team of nine scientists
note that
"four independent lines
of evidence indicate
intensifying terrestrial
biospheric activity,
namely the increasing
positive trends in
(a) the global net
land carbon sink;
(b) the amplitude of the
seasonal cycle of
atmospheric CO2
in the Northern Hemisphere;
(c) satellite-observed
leaf area; and
(d) global gross
primary production,"
citing multiple studies
of supporting research.
DETAILS:
The nine researchers
used the Community
Atmosphere-Biosphere
Land Exchange model
( CABLE )
to project the net land sink,
over the period 2006-2099,
under the IPCC's RCP2.6
low emission scenario.
( RCP2.6 assumes
a CO2 peak of 440 ppm,
and a temperature increase
(above 1990) of +2.4°C.
in 2050. )
The team found the
terrestrial biosphere
"would continue to
sequester carbon
well into the second half
of the century",
leading to a net land sink
much larger than the
average CMIP5 climate
model ensemble,
under the RCP2.6
CO2 level growth
assumption.
Chart 1, below:
CO2 fertilization effect
on global gross primary
production (GPP),
attributed to:
(i) climate effect and
atmospheric CO2
x climate interaction effect
(orange);
(ii) CO2 greening effect
(light green);
(iii) CO2 leaf-level effect
(dark green).
Chart 2, below:
Spatial distribution
(panel a),
latitudinal distribution
of component factors
(panel b), and
driver-attribution
(panel c)
of the 1980-2016
trend in global gross
primary production
( GPP ).
Tot = total effect;
C = atmospheric CO2 only;
T = temperature;
C x T = atmospheric CO2
and temperature interaction;
P = precipitation;
LUC = land use change.
Only the
major drivers
are isolated.
Additional drivers
( nitrogen deposition;
specific humidity;
wind speed;
incoming short
and long wave
radiation )
and their interactions
are not isolated
but may contribute
to the total effect.
Error bars represent
standard errors from
linear regression fits
to each driver component.
