Consequently, those models used large aerosol cooling to offset greenhouse gas warming in the historical period, and assumes aerosol cooling will decline in the future.
This allows climate models to have high sensitivity to greenhouse gases while still roughly matching the historic temperature record.
The oceans account for over 90% of the climate system heat uptake.
The two periods used for the analysis were 1859-18-2011.
For relatively well-preserved bones, the ‘chunk’ method of collagen preparation continues to be an acceptable alternative to more sophisticated collagen extraction protocols for C and N isotope analysis.
Summary High estimates of climate sensitivity to greenhouse gases assume aerosols caused a large cooling effect, which canceled some of the previous warming effect, and little or no natural climate change.
Aerosols have a direct effect and an indirect effect from aerosol-cloud interactions, both of which are estimated to cause cooling.
The latter method was developed for problematic (i.e.
poorly-preserved) samples and while it is more rigorous, it is also significantly more expensive and more labor-intensive.
A more policy-relevant parameter is the Transient Climate Response (TCR) which is the global temperature change at the time of the CO at the current growth rate of 0.55%/year would take 126 years.
The analysis gives the TCR best estimate at 1.21 °C with a likely range [17 – 83%] of 1.05 to 1.45 °C.