Last edited Sat Jul 4, 2020, 11:31 PM - Edit history (2)
proof that we're past the tipping point. At least no reputable (or not) climate scientist that I know of has said so.
Here is what they say at NOAA.gov (I broke it from one paragraph to three paragraphs for readability as I just don't handle big bricks of solid text well)
https://www.esrl.noaa.gov/gmd/ccgg/covid2.html
There have been many inquiries whether we can see in our CO2 measurements at Mauna Loa and elsewhere the slowdown in CO2 emissions from the burning of fossil fuels. That drop in emissions needs to be large enough to stand out from natural CO2 variability caused by how plants and soils respond to seasonal and annual variations of temperature, humidity, soil moisture, etc. These natural variations are large, and so far the "missing" emissions do not stand out.
Here is an example: If emissions are lower by 25%, then we would expect the monthly mean CO2 for March at Mauna Loa to be lowered by about 0.2 ppm, and again in April, etc. Thus, when we compare the average seasonal cycle of many years we would expect a difference to accumulate after a number of months, each missing 0.2 ppm.
The International Energy Agency expects global CO2 emissions to drop by 8% this year. Clearly, we cannot see a global effect like that in less than a year. CO2 would continue to increase at almost the same rate, which illustrates that to tackle our global heating emergency aggressive investments need to be made in alternative energy sources.
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The below illustrates the considerable variability in the growth of the Mauna Loa CO2 level from year to year:
# Growth Rate tab - Annual Mean growth rate of CO2 in ppm/year :
2014: 2.19, 2015 and 2016: both 2.99, 2017: 1.89, 2018: 2.86, 2019: 2.46
https://www.esrl.noaa.gov/gmd/ccgg/trends/gr.html visited 7/4/20
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Rise of carbon dioxide in the atmosphere continues unabated, Posted by Eleanor Imster in Earth | Human World, Earthsky.org, 6/9/20
https://earthsky.org/earth/rising-carbon-dioxide-co2-record-high-june2020
If humans were to suddenly stop emitting CO2, it would take thousands of years for our CO2 emissions so far to be absorbed into the deep ocean and atmospheric CO2 to return to pre-industrial levels.
If emissions reductions of 20% to 30% were sustained for six to 12 months, then the rate of increase of CO2 measured at Mauna Loa would be slowed.
Geochemist Ralph Keeling runs the Scripps Oceanography program at Mauna Loa. He said:
"People may be surprised to hear that the response to the coronavirus outbreak hasn’t done more to influence CO2 levels. But the buildup of CO2 is a bit like trash in a landfill. As we keep emitting, it keeps piling up. The crisis has slowed emissions, but not enough to show up perceptibly at Mauna Loa."
Even though
terrestrial plants and the global ocean absorb an amount of CO2 equivalent to about half of the 40 billion tons of CO2 pollution emitted by humans each year, the rate of CO2 increase in the atmosphere has been steadily accelerating. (emphasis added by Progree)
The point of my emphasis is that given that only half of the CO2 that we emit each year in a normal year lately (pre-Covid) is absorbed, it would take a sustained cutback of more than 50% in emissions for the actual CO2 ppm level in the atmosphere to drop, as opposed to go up more slowly.
Admittedly, this just covers the CO2 situation. Methane might be whole 'nuther story.
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