Sunday, May 01, 2011

On Deniers, Scientific Consensus and Climate Change

This article articulates widespread confusion on three key concepts related to the scientific investigation of climate variability: climate change, denial, and consensus.

The term "climate change" is used here as short hand for anthropogenic or human caused climate change. A cursory glance through any basic Earth Science text clearly demonstrates that the Earth's climates have changed over time, sometimes drastically and sometimes (geologically) rapidly. Obviously, natural climate change is beyond any human influence. All humans can do is accommodate, as we have done for millennia. The popular perception created by use of this term is that humans have caused the presently observed climate change and therefore we can do something to stop it.

The term "denier" is a pejorative that obfuscates the nature of opposition to the popular perception of climate change. There are very few, if any, who deny that climate changes.  Those who do not accept the anthropogenic global warming (AGW) hypothesis (human produced greenhouse gases cause increases in average global surface temperature) range from the politically and economically motivated to scientists publishing in current peer-reviewed professional literature.

Which brings up "consensus." The "scientific consensus around climate change" is frequently touted as a reason why everyone should accept AGW as a scientifically established fact.

However, this turns out not to be the case. There is no consensus on any causal relationship between human produced greenhouse gases and increasing average global surface temperature. There are as many, or more, citations in the literature questioning the validity of the AGW hypothesis as there are supporting it. The deep geological record suggests that atmospheric CO2 levels rise 800 to 1,000 years after temperature rise, over the past 2.5 million years. While CO2 may be in part responsible for our warm Earth, it is not, and never has been, responsible for runaway global warming.

The Earth's atmosphere/ocean heat circulation system is a complex adaptive systems that responds to many factors, anthropogenic, terrestrial and cosmic. We do not at present understand how this complex system works, how the many and various feedback mechanisms operate, independently and together, to produce observed climate variation. Since we don't understand the mechanisms of natural climate change, we cannot assess the influence of anthropogenic greenhouse gases on our climate today, nor can we do anything to "stop" climate change or influence its rate or direction.

Global circulation climate models are often cited as evidence of AGW. However, computer models are not evidence; they are hypotheses to be tested with present and future observations. To date, global circulation models have been unable to predict present climate trends (such as steady average global surface temperature for the past 30 years, declining average sea level, etc.). They are therefore proven inadequate to predict future climate variation.

Undue focus on the AGW hypothesis draws attention from impacts of human economic growth and  development that must be curtailed: air, water and land pollution, habitat loss, deforestation, topsoil depletion, fresh water depletion, etc. We can do something about this, each one of us, every day. It doesn't take massive government subsidies to encourage individual responsibility for our actions and the results of consumer choice. If AGW is proven false or negligible and humans drift away from the popular global warming fantasy, as they are now, the impetus for societal change will diminish.

Government subsidies for "carbon-free" energy will not reduce human pollution and natural habitat loss. Mining, manufacture, assembly and installation of massive wind and solar farms across undeveloped land will create more immediate environmental harm than centuries of climate change.

The solution is not more industrial development and economic growth. The answer is less: less pollution, less habitat loss, fewer people, fewer cars, fewer roads. We have exceeded the limits. Our only course is to move backward from the abyss, or, if that sticks in the craw, turn around and take the first steps forward.

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