The Views of the Climate Deniers are Not Supported by the Hourly Temperature Data: Evidence from Hawaii

Author: Kevin F. Forbes, Ph.D.

Abstract

A small group of climate scientists and influencers has vigorously disputed the scientific consensus on climate change. They accept that more CO2 in the atmosphere has consequences for the climate but strongly deny that the magnitude of the effect is significant. Using hourly CO2 data from the Mauna Loa Observatory in Hawaii, this paper examines whether this belief is supported by the hourly temperature data at the nearby Hilo International Airport. ARCH/GARCH/ARMAX methods are employed because the hourly temperature data, even in Hawaii, is both highly autoregressive and volatile. The temperature data are analyzed using an archive of day-ahead hourly weather forecast data to control for expected meteorological outcomes. The model is estimated using 42,928 hourly observations from August 7, 2009, through December 31, 2014. CO2 concentrations are found to have statistically significant implications for hourly temperature. The model is evaluated using hourly data from January 1, 2015, through December 31, 2017. The analysis does not support the view that the effects of CO2 on temperature are trivial in magnitude. Instead, the findings add to the consilience of evidence supporting the scientific consensus on climate change.

Key Points:

• Hourly CO2 concentrations have nontrivial implications for hourly temperature.

• The effect of CO2 on actual temperature is higher, the higher the level of forecasted temperature and humidity.

• The out-of-sample hourly temperature predictions are more accurate when the estimated statistically significant effects of hourly CO2 are factored into the predictions.