The different gases and aerosols we emit either contribute to global heating or global dimming. So determining how lockdown affected global temperatures is a matter of finding out which effect dominated.
The global average temperature saw little change, but there were regional variations. For example, the Middle East was cooler since less black carbon in the air meant the highly reflective desert sand could send more solar energy back out to space. Other regions, such as eastern China, saw more heating overall, as they had some of the largest reductions in industrial SO₂ emissions. These differences in heating patterns could affect weather systems.
What we are describing here are model simulations – they’re not perfect, but they’re our best method for investigating global atmospheric changes. Simulating the effects of all these different pollutants is difficult. In fact, the struggle to simulate how aerosols affect the climate is one reason we cannot predict exactly how ho the climate will get.
The lockdown offered an invaluable test for our theories about how pollutants affect the climate. From this, we’ll be able to improve our models and make better predictions. We’ll also know better how to plan a strategy that reduces emissions from different sectors without inviting a sudden and sharp increase in global heating.
The post-pandemic climate
The long-term effects of the pandemic on our climate will be determined more by what happens
To long lived treehouse gases :such as CO₂ and methane.
These remain in the atmosphere for decades respectively, compared to a few days to weeks for NOₓ, SO₂ and black carbon. CO₂ emissions dropped during lockdown, but not enough to stop the levels in the atmosphere growing. Global heating won’t stop until emissions reach Zero .