On January 1st 2020, international shipping vessels were required to substantially reduce the amount of particulate they emit to improve air quality. In this work we demonstrate how this regulatory change contributed to the anomalous warming observed in recent months using climate model simulations that include such a change. Future policies should also perhaps consider their impact on climate and that climate modelers should include those changes promptly in future modeling efforts.

It was recently suggested that global warming can be explained by the non-anthropogenic factor of seismic activity. If that were the case, it would have profound implications. We have accessed the validity of the claim using a statistical technique that evaluates the existence of causal connections between variables, finding no evidence for any causal relationship between seismic activity and global warming.

Simultaneous heatwaves or cold spells in remote geographical regions have potentially far-reaching impacts on society and the environment. Notwithstanding this, we have little knowledge of when and where these extreme events have occurred in the past decades. Here, we present a summary of past simultaneous heatwaves or cold spells, and provide a computer program to enable other researchers to study them.