Future change in the solar wind and Central England temperature: implications for climate change attribution

TL;DR

This study analyzes long-term temperature records and solar wind data to attribute recent climate changes primarily to natural variability, with minor influence from anthropogenic global warming, and projects future temperature trends.

Contribution

It introduces a spectral decomposition method to distinguish natural and anthropogenic effects on climate using long-term temperature records and solar wind proxies.

Findings

Recent temperature trends mainly due to natural variability.

Projected cooling of 0.5°C by 2060 before warming resumes.

Complex relationship between solar wind and temperature variations.

Abstract

The recent increase in global temperature is attributed to anthropological global warming, (A.G.W), with a minor role for natural trends in temperature. The I.P.P.C estimates natural temperature (NAT) from climate models and attributes the difference from recent recorded temperature to A.G.W. We use the temperature record to assess if trends in temperature are due to NAT or A.G.W effects. The method requires long records like the 362-year Central England temperature (C.E.T) record. The C.E.T was divided into a 262 year-long early part when only NAT was significant, and a 100 year-long later part. The early part was decomposed into eight components in the spectral range 15 to 257 years and the components were forward projected to the next 100 years. The projected NAT replicated the recorded cooling from 1950 to 1980 and the rapid increase from 1980 to 2010, indicating that the recent strong 50-year trend in C.E.T was primarily NAT. Based on the small difference between the projected NAT and the recorded C.E.T a minor role was attributed to A.G.W and a climate sensitivity to CO2 doubling of 0.7 +/- 0.2 K estimated. Components, at 514 and 1028 years, were derived from the C.E.T record providing a means for validation of long projections against proxy records of past temperature. Future projection of combined NAT and A.G.W indicated a cooling of C.E.T by 0.5 C from now to year 2060 before A.G.W becomes dominant. The possible cause of an imminent decrease in C.E.T was explored by applying the same method of component estimation to temperature data from Melbourne, Australia (MET) and the geomagnetic a.a index, a proxy for the solar wind. Comparing cyclic variations of the a.a index and the C.E.T and MET data indicated a complex relationship with the strong recent increase in C.E.T and MET lagging the increase in the solar wind by ~15 years.