Abstract
The latest report from the Intergovernmental Panel on Climate Change states with high confidence that the warming of global temperatures since 1901 has been driven by increased radiative forcing. The gases responsible for this enhanced forcing are ‘greenhouse gases’ of anthropogenic origin, and include carbon dioxide, methane, and halocarbons. The Nongovernmental International Panel on Climate Change has challenged these findings and concludes that the forcing from greenhouse gases is minimal and diminishing. They add that modelling attempts of past and future climate states are inaccurate and do not incorporate important solar inputs, such as magnetic strength and total irradiance. One geophysical variable that has been overlooked by both groups is geothermal flux.
This study will show that increasing seismic activity for the globe’s high geothermal flux areas (HGFA), an indicator of increasing geothermal forcing, is highly correlated with average global temperatures from 1979 to 2015 (r = 0.785). By comparison, the correlation between carbon dioxide loading and global temperatures for the same period is lower (r = 0.739). Multiple regression indicates that HGFA seismicity is a significant predictor of global temperatures (P < 0.05), but carbon dioxide concentrations do not significantly improve the explained variance (P > 0.1). A compelling case for geothermal forcing lies in the fact that 1) geothermal heat can trigger thermobaric convection and strengthen oceanic overturning, important mechanisms for transferring ocean heat to the overlying atmosphere, and 2) seismic activity is the leading indicator, while global temperature is the laggard.
Introduction
The prevailing thought in the scientific community is that human-induced alterations to the earth-atmosphere system are the primary drivers of climate change in the 20th and 21st centuries. The Intergovernmental Panel on Climate Change (IPCC) recently completed its Fifth Assessment Report (AR5) and they argue that there has been unprecedented warming of both the oceans and the atmosphere since the 1950s [1].The bulk of this warming has occurred over the past three decades, and the Northern Hemisphere has probably seen its warmest temperatures in the past 1,400 years. Temperatures at these levels have caused sea levels to rise, snow and ice extent to decline, and they have amplified extreme events in the atmosphere, to include increases in tropical cyclone intensity, drought intensity, hot spells, and heavy precipitation episodes. Central to the report’s findings is that there is a very high chance that recent warming has been caused by enhanced radiative forcing (RF) via increased concentrations of greenhouse gases (GHG), to include carbon dioxide (CO2, primary), methane, nitrous oxide, and halocarbons (secondary). The jump in GHG loadings is mostly anthropogenic and is strongly driven by the burning of fossil fuels (primary) and land-use change (secondary).