Limits on CO2 Climate Forcing from Recent Temperature Data of Earth

TL;DR

This paper analyzes Earth's temperature data, showing that recent temperature variations are mainly due to natural climate effects, with only a small underlying trend potentially attributable to CO2 forcing without feedback mechanisms.

Contribution

It distinguishes natural climate variability from CO2 forcing effects using recent temperature data and identifies a small positive trend consistent with CO2 influence without feedback.

Findings

1998 temperature maximum explained by El Nino/La Nina effects

Background variations mainly from northern extratropics

Small positive trend consistent with CO2 forcing without feedback

Abstract

The global atmospheric temperature anomalies of Earth reached a maximum in 1998 which has not been exceeded during the subsequent 10 years. The global anomalies are calculated from the average of climate effects occurring in the tropical and the extratropical latitude bands. El Nino/La Nina effects in the tropical band are shown to explain the 1998 maximum while variations in the background of the global anomalies largely come from climate effects in the northern extratropics. These effects do not have the signature associated with CO2 climate forcing. However, the data show a small underlying positive trend that is consistent with CO2 climate forcing with no-feedback.