Theory vs. Evidence: the great climate debate


From the “Climategate” leaker’s “readme” manifesto:


“Over 2.5 billion people live on less than $2 a day.”

“Every day nearly 16000 children die from hunger and related causes.”

“One dollar can save a life” -- the opposite must also be true.

“Poverty is a death sentence.”

“Nations must invest $37 trillion in energy technologies by 2030 to stabilize greenhouse gas emissions at sustainable levels.”

Today's decisions should be based on all the information we can get, not on hiding the decline.


GHGs: Over the last century, mankind's activities -- mainly fossil fuel use -- have increased atmospheric CO2 from 0.03% of the Earth's atmosphere to 0.04% (400 ppmv) today.

Theory: Increased GHG levels (mainly carbon dioxide) will cause dramatic, destructive increases in the Earth’s temperature, in sea-level rise, and in severe weather events.

Evidence: All of the worrisome negative effects of anthropogenic CO2 are entirely theoretical. The benefits of anthropogenic CO2, however, are saving millions of lives from starvation, already.

The warming from anthropogenic GHGs is modest and benign. When ENSO and volcanic aerosols are taken into account there’s been no significant warming in ~22 years [Santor, Schmidt, et al 2014]. Sea-level rise hasn’t accelerated in over 85 years and is unaffected by anthropogenic GHGs. Severe weather is trending slightly down, not up.

OTOH, the benefits are important and well-documented. 15-20% of current agricultural productivity is directly due to the beneficial “fertilization” effects of anthropogenic CO2. 

90% of the increase has been since WWII. 15%-20% of current agricultural productivity is due to the "fertilization effect" of anthropogenic CO2. About 40% of the Earth's land is currently used for agriculture. So we can calculate that without anthropogenic CO2, 47%-50% of the Earth's land would need to be devoted to agriculture, to make up for the loss of productivity, i.e., an additional 10-15 million km2 of land.

Unfortunately, much of the Earth's land is not suitable for agriculture, with a very notable exception: rainforests. Rainforests cover about 9 million km² of the Earth's surface. If CO2 were at pre-industrial levels (about 0.03%), then cutting down all the world's rainforests and converting them to agriculture would almost make up for the lost of agricultural productivity due to lack of anthropogenic CO2.

Anyone who cares about starvation and poverty, and anyone who cares about the Earth's rainforests, should be very thankful that mankind's use of fossil fuels has raised atmospheric CO2 from about 0.03% of the atmosphere (a century ago) to the current 0.04%. That’s why I and 31,486 other American scientists (including engineers in relevant specialties) have signed the Global Warming Petition, signifying our agreement with this statement:


"There is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gases is causing or will, in the foreseeable future, cause catastrophic heating of the Earth's atmosphere and disruption of the Earth's climate. Moreover, there is substantial scientific evidence that increases in atmospheric carbon dioxide produce many beneficial effects upon the natural plant and animal environments of the Earth."

Here's a picture from an old issue of Scientific American, showing the effect of anthropogenic carbon dioxide on crops; they called it “the precious air fertilizer.”

1. Yield of potatoes in fields over which the air was fertilized with carbonic acid gas and left unfertilized.


Here's an especially high-quality 168-year long record of sea-level, from a tide gauge in Europe:

Every high-quality, long-term coastal sea-level measurement record in the world shows the same thing: adding 100 ppmv of CO2 (and a lot of methane) to the atmosphere has not detectably affected sea-level rise.


Have you noticed how long it's been since a major hurricane hit the USA? 125 months! It's the longest in recorded history. Worldwide storminess actually seems to have decreased slightly, rather than increased, as greenhouse gas levels have gone up:


“Future generations will wonder in bemused amazement that the early twenty-first century's developed world went into hysterical panic over a globally averaged temperature increase of a few tenths of a degree and, on the basis of gross exaggerations of highly uncertain computer projections combined into implausible chains of inference, proceeded to contemplate a roll back of the industrial age.”  -Dr. Richard Lindzen (Alfred P. Sloan Professor of Meteorology, Department of Earth, Atmospheric and Planetary Sciences, MIT)


Dave Burton          April 6, 2016

NC Sea Level Rise Impact Study Advisory Committee member, U.N. IPCC AR5 WG1 Expert Reviewer, NC-20 Science Advisor.      M: 919-244-3316