«Even accounting for all uncertainties and limitations, the temperature change could not be realistically
explained by natural variability alone, implying a long - term human signal,» Will told me.
I'd just like to make sure I understood your post correctly: the common answer to the «contrarian talking point» that much of the observed recent climate change could just be caused
by natural variability in the climate system is that this would imply, broadly speaking, heat being moved from the oceans to the atmosphere — whereas we observe the opposite, oceans storing heat.
These variations originate primarily from fluctuations in carbon uptake by land ecosystems
driven by the natural variability of the climate system, rather than by oceans or from changes in the levels of human - made carbon emissions.
One advantage of the theory that there has been a warming trend occasionally obscured in the short
term by natural variability is that we have a mechanism that explains why there should be a warming trend (CO2) and mechanisms for explaining the variability (IIRC ENSO is responsible for quite a lot of it).
Anthropogenic global warming inherently has decadal time scales and can be readily masked
by natural variability over periods less than a decade or so.
Most projections suggest that that point will be reached sometime in the middle of the century, and, as another recent paper found, scientists» ability to pin down that date is
limited by the natural variability of the sea ice system to within a couple of decades.
For decades to come, we're locked into generally rising temperatures, with shorter - term temperature shifts * — up or down — shaped
most by natural variability in the system (as with the recent plateau in temperatures).
It seems to me that the onus should be on those who are confidently claiming that there has been a genuine hiatus in surface temperatures to demonstrate that the apparent flattening is not
explainable by the natural variability in the data.
It is also small enough to have been caused
instead by natural variability (although it is also plausible that natural variability has temporarily masked some of the warming caused by GHG emissions).
«In a way similar to that in which medieval astronomers rationalized planets» being in the «wrong» position as they orbited the Earth, it can be argued that global warming has continued but that its effect has been temporarily
offset by natural variability.
Finally, the components within each stream are identified as belonging to Phase I or II research, and the limits
placed by the natural variability of the climate system on what can be learned from low - level Phase II field - testing are roughly assessed.
Two essential points are: 1) When energy balance is certainly a limiting factor, one warming step is much more likely
produced by natural variability than two successive steps.
Direct radiative forcing
induced by natural variability of solar activity has been extremely low during the last 200 years (27), and there has been no evidence for a large - scale destruction of stratospheric ozone in the Northern hemisphere (28).
However, from 1971 to 2020, they found that the average rate of change over North America, for example, was about 0.3 degrees Celsius per decade - that's higher than can be accounted for
by natural variability alone.
One advantage of the theory that there has been a warming trend occasionally obscured in the short
term by natural variability is that we have a mechanism that explains why there should be a warming trend (CO2) and mechanisms for explaining the variability (IIRC ENSO is responsible for quite a lot of it).