"Radiative imbalance" refers to a situation where Earth's energy system, particularly the balance between incoming solar radiation and outgoing heat radiation, is disrupted. It means that more energy is being absorbed by the Earth than what is being emitted back into space, leading to a build-up of excess heat in the atmosphere and oceans. This imbalance is a key factor in climate change and can cause various impacts such as rising temperatures, melting ice, and extreme weather events.
Full definition
Thus, it can be concluded that the observed 15 - year trend in
radiative imbalance of the tropics is probably a signature of natural rather than anthropogenic climate variations.
So the current hiatus in surface warming is a transient and global warming has not gone away: there is a continuing
radiative imbalance at the top of atmosphere.
Net ocean heat content changes are very closely tied to the
net radiative imbalance of the planet since the ocean component of the climate system has by far the biggest heat capacity.
The sensitivity of the climate system to an
imposed radiative imbalance remains the largest source of uncertainty in projections of future anthropogenic climate change.
We can estimate this independently using the changes in ocean heat content over the last decade or so (roughly equal to the
current radiative imbalance) of ~ 0.7 W / m2, implying that this «unrealised» forcing will lead to another 0.7 × 0.75 ºC — i.e. 0.5 ºC.
OLR must be very close to equal to Fo or there will be a substantial
radiative imbalance which will lead to heat loss or gain depending on the sign of the imbalance.
However, primarily in spacecraft (of which Earth is such) and so the entire «controversy» over a CO2 - induced
radiative imbalance over our spacecrafts heat - rejection capability quite frankly has been «cramping my 88 * ss» for 20 years now.
It is double speak for a climate scientist to assert (correctly I might add) that natural variability like ENSO will alter the TOA
radiative imbalance through changes in clouds, humidity, evaporation, rainfall, ect., but then out of the other side of the mouth imply that natural variability doesn't really matter to the multi-decadal projections.
In this case the CO2 concentration is instantaneously quadrupled and kept constant for 150 years of simulation, and both equilibrium climate sensitivity and RF are diagnosed from a linear fit of perturbations in global mean surface temperature to the
instantaneous radiative imbalance at the TOA.
If volcanic forcing produces only half the GMST and
radiative imbalance response in CMIP5 models as does the same forcing by CO2, for instance — implying that volcanic forcing has an efficacy of 0.5 for the measure of forcing used — then the calculation of total forcing involved will automatically down weight by 50 % the contribution from volcanic forcing.
If maximum temperatures have not exceeded that earlier peak, CO2 has not caused any regional «accumulation of heat» due to the
hypothesized radiative imbalance; and Parmesan is still very wrong for suggesting global warming was extirpating butterflies.
We can not count on the heat from the
continuing radiative imbalance continuing to go into the deeps (once again, uncertainty cuts both ways), nor even that all of the heat sequestered there will stay there.
Here we analyse twenty - first - century climate - model simulations that maintain a
consistent radiative imbalance at the top - of - atmosphere of about 1 W m − 2 as observed for the past decade.
However, practices differ significantly on some key aspects, in particular, in the use of initialized forecast analyses as a tool, the explicit use of the historical transient record, and the use of the present
day radiative imbalance vs. the implied balance in the pre-industrial as a target.»
Should we not be unrealising a lot
more radiative imbalance by creating energy moving surface heat to the ocean abyss through heat engines?
To presume 0 d (local SST anomaly) / d (global anomaly) requires an extra assumption that the Atlantic is somehow special, such that all the effects of global
radiative imbalance wind up elsewhere in the ocean.
Using TOA
radiative imbalances instead of ocean heat uptake (which can not be directly observed with sufficient precision) would be pointless.
Meehl et al., 2011 (doi: 10.1038 / NCLIMATE1229) show that with a
similar radiative imbalance, hiatus periods and non-hiatus periods can occur, and that in the first case larger heat storage in the deep ocean takes place.