The recent trend in sea level rise is consistent
with ocean heat uptake, so we shouldn't be surprised that the recent trend in sea level rise has slowed somewhat too.
Hence the deduction of the estimated change in
ocean heat uptake from the estimated change in forcing before comparison with the change in global temperature to derive sensitivity.
New research shows that
ocean heat uptake across three oceans is the likely cause of the «warming hiatus» — the current decade - long slowdown in global surface warming.
Warming in the pipeline very largely
reflects ocean heat uptake, which reduces the extent to which surface temperatures need to rise in order to counteract increased forcing from CO2 etc..
The only reason
why ocean heat uptake does have an impact is the fact that it is highly concentrated at the surface, where the warming is therefore noticeable (see Fig. 1).
It has been recognized for some time that model simulations result in much greater warming in the high latitudes of the Northern Hemisphere than in the South, due to
ocean heat uptake by the Southern Ocean.
«Therefore, unless models miss effects of other forcing agents, it is likely that this [less
efficient ocean heat uptake] process will occur and act to accelerate surface warming in coming decades.»
«Since climate will be far from equilibrium during this period, the weakening in κ
[ocean heat uptake efficiency] should not be interpreted as saturation of heat uptake.
«Results imply that global and regional warming rates depend sensitively on regional ocean processes setting the [
ocean heat uptake] pattern, and that equilibrium climate sensitivity can not be reliably estimated from transient observations.»
Because the 40degree 90degree N region accounts for up to 40 % of the simulated
global ocean heat uptake over one hundred years, the process described here influences the global heat uptake efficiency.
In addition, some studies also use the estimated
ocean heat uptake since 1955 based on Levitus et al. (2000, 2005)(Chapter 5), and temperature changes in the free atmosphere (Chapter 3; see also Table 9.3).
Rapid emissions reduction is required to restore Earth's energy balance and
avoid ocean heat uptake that would practically guarantee irreversible effects.
al. correctly predict that the land surface will warm more than the ocean surface, and that the southern ocean warming would be temporarily suppressed due to the
slower ocean heat uptake.
Considering the past half century in this context is convenient because we have direct, albeit imprecise, estimates of
ocean heat uptake over this period.
Thus, there seem to be a lot of assumptions about
ocean heat uptake which lead to the unsupported conclusion that there is «rapid equilibration of the climate system to applied forcings».
But a quick computation suggests that with ECS at 1.6 C and reasonably mainstream
ocean heat uptake parameters, TCR would likely be in the range 1.25 -1.4 C.
The evident relationship between effective climate sensitivity and
ocean heat uptake leads to the transient climate response (TCR) having a smaller spread among the model results than the climate models climate sensitivity alone would suggest (see Section 9.3.1).
Phrases with «ocean heat uptake»