These are some of my tweets today: @
Todays main science story
A paper published today in Earth System Science Data Discussions analyzes the 2014 carbon budget and predicts man-made CO2 emissions from fossil-fuels and cement production have increased by 65% since 1990. However, atmospheric levels of CO2 have only increased by 11% since 1990, indicating that ~88% of man-made emissions have been absorbed by natural sinks, far greater than IPCC belief that natural sinks absorb 50% of man-made emissions.
Thus, natural sinks [such as the up to 30% greening of the planet over past few decades] are expanding faster than the IPCC anticipated, CO2 lifetime in the atmosphere is much less than the IPCC believes, or the source of the increase is primarily natural due to ocean outgassing, or some combination of the three.
Thus, the IPCC assumptions about greenhouse “pathways” and “warming in the pipeline” are exaggerated, erroneous, and overheated.
Further, the 65% increase in CO2 emissions was only associated with 0.2C warming since 1990. If we make the false assumption that 100% of the warming since 1990 was due to man-made CO2 emissions, we can calculate the climate sensitivity to man-made emissions as
~0.2C = x*ln(1.65), where x = 0.399 [13 times less than the 5.35 fudge factor (x) the IPCC uses]
Thus a doubling of man-made emissions [as opposed to net atmospheric levels] of CO2, assuming all warming is due to man-made CO2 emissions, would produce a temperature rise of only 0.28C, in line with several other observational estimates of climate sensitivity to CO2 levels: