Abstract
Survey evidence has indicated that a significant percentage of the
population does not fully embrace the scientific consensus regarding
climate change. This paper assesses whether the hourly temperature data
support this denial. The analysis examines the relationship between
hourly CO2 concentration levels and temperature using
hourly data from the NOAA-operated Barrow observatory in Alaska. At this
observatory, the average annual temperature over the 2015-2020 period
was about 3.37 oC higher than in 1985–1990. A
time-series model to explain hourly temperature is formulated using the
following explanatory variables: the hourly level of total downward
solar irradiance, the CO2 value lagged by one hour,
proxies for the diurnal variation in temperature, proxies for the
seasonal temperature variation, and proxies for possible
non-anthropomorphic drivers of temperature. The purpose of the
time-series approach is to capture the data’s heteroskedastic and
autoregressive nature, which would otherwise “mask”
CO2’s “signal” in the data. The model is estimated
using hourly data from 1985 through 2015. The results are consistent
with the hypothesis that increases in CO2 concentration
levels have nontrivial consequences for hourly temperature. The
estimated annual contributions of factors exclusive of
CO2 and downward total solar irradiance are very small.
The model was evaluated using out-of-sample hourly data from 1 Jan 2016
through 31 Aug 2017. The model’s out-of-sample hourly temperature
predictions are highly accurate, but this accuracy is significantly
degraded if the estimated CO2 effects are ignored. In
short, the results are consistent with the scientific consensus on
climate change.