IPCC is wrong about global warming because it doesn’t understand aerosols

Between 2010 and 2023 global warming grew 67% faster than 40 years earlier

The global warming anomalies of the last 2 years are not anomalies but the confirmation that the Earth’s temperature is increasing rapidly. Between 2010 and 2023, global warming increased by 0.3°C per decade, 67% faster than 0.18 °C per decade in the 1970-2010 period. And behind this acceleration there can be no other factors than the decrease in the concentration of aerosols in the atmosphere, due to less anthropogenic pollution.

This is stated in the white paper Global Warming Acceleration: Hope vs Hopium published by climate scientist James Hansen, one of the pioneers of the study of global warming. Hansen recently published several studies that claim that the climate crisis is accelerating and that our forecasting models cannot fully grasp what is happening to the planet’s climate system.

Fueling a debate where this position – often branded as “catastrophist” – is opposed to that of those who, like Michael Mann, argue instead that what we see today are really anomalies and that our current understanding of the Earth’s climate is quite accurate.

Aerosols and global warming “in the pipeline”

Hansen says we’re living on credit. The data of the concentration of CO2 in the atmosphere and the energy balance of the Planet (the amount of solar radiation captured by the Earth) would suggest that there is a share of global warming “dormant” (“in the construction site“, as the title of a study of his) which is slowly manifesting its effects but which we can no longer avoid in any way. We would then be sentenced to exceed 1.5°C already between 2027 and 2028.

And what we can do is to focus massively on technologies of direct capture of CO2 from the air (CDR, carbon dioxide removal), geoengineering solutions to shield part of solar radiation (SRM, solar radiation management) and combine renewable and nuclear for decarbonisation of the global energy mix.

The white paper takes the data from the last 2 years and claims that they confirm the predictions of his past studies. “The accumulated evidence supports the interpretation of our study: the decrease in man-made aerosols has increased Earth’s energy imbalance and accelerated global warming over the past decade,” writes Hansen.

The aerosol node is central. Hansen argues that, as they are constructed, climate forecasting models fail to account for this factor independently. But the leap in global warming in 2023 and these first months of 2024 can only be explained by this factor. Aerosols have a cooling effect because they reflect part of the solar radiation in space but are difficult to measure directly, also because they interact with the cloud cover that has a high natural variability. But what then is their effect on the Earth’s climate?

According to the IPCC, removing aerosols means increasing the Earth’s energy balance by 0.079 W/m2, but for Hansen the data of recent years – after the entry into force of the new rules for ship emissions, one of the largest aerosol emitters – point to values 10 times higher, at least 0.7 W/m2. As a result, while the IPCC believes that a doubling of CO2 in the atmosphere compared to the pre-industrial period leads to a global warming of 3°C, the true value should be around 4.8°C. The reference CO2 concentration is 275 parts per million, today we are at about 420.

“Time is pressing to make the public and politicians aware of the threat posed by the delayed response of our climate system and the actions that should replace the current wishful thinking,” writes Hansen. “It is realistic to hope that we can greatly improve understanding in this decade, a period that should be long enough to highlight the uselessness of current policies, as well as to test the physics of ongoing climate change”.