Demystifying Global Warming

Abstract

Public perception has not kept pace with scientific consensus on the anthrogenic causes of global warming. The complexity and uncertainty that characterize climate science provide skeptics with ample cover, reinforcing the political and economic incentives to deny this premise. Meanwhile, while most scientifically literate people are aware that climate change is caused by heat buildup in the earth system (including air, land, and water), they may not fully comprehend the connection. A simplified analysis and predictive model are proposed that could narrow the gap between the experts who know and the laypeople who are asked to trust them.

The earth’s radiative imbalance can be explained by the accumulation of manmade greenhouse gases (GHG) in the atmosphere. A 60-year graph illustrates how closely the CO2 content in the atmosphere correlates with accumulated emissions from human activity. A 60-year regression graph reveals that 91% of the change in global temperatures can be explained by the CO2 in the atmosphere. The other 9% of the variation undoubtedly comes from natural cycles and uneven heat exchange between the atmosphere and the oceans, which serve as a heat bank. A graph comparing global average temperature trends between the earth’s surface and the oceans down to 2,000 meters over the last 19 years, shows the oceans act as a thermal ballast and provide a more reliable measure of heat buildup.

Five principal factors account for most of the global warming we observe. The earth responds to human emissions of greenhouse gases and aerosols, as well as alteration of the landscape, through two critical feedback mechanisms. Black body radiation increases with global temperature and has a cooling effect. Water vapor feedback compounds warming because hotter air evaporates more water from the oceans, and water vapor behaves as a greenhouse gas. These five factors lend themselves to a relatively simple predictive model that closely matches a blend of 50 comprehensive models. Most of the modeling complexity and uncertainty, while of considerable academic interest, has minimal effect on the bottom line. A five-factor heat balance model is formulated and used along with a logistic curve to present alternative pathways to limit global warming to 2⁰C. A graph of these pathways shows that civilization needs to cut GHG in half by 2040. This has been confirmed by the International Energy Agency in laying out what it calls the “sustainable development scenario.”

Keywords: climate change, global warming, simplified heat balance