(ORDO NEWS) — Planetary-scale engineering schemes designed to cool the Earth‘s surface and reduce the impact of global warming are potentially dangerous and should be blocked by governments, more than 60 policy experts and scientists said Monday.
Even if injecting billions of sulfur particles into the mid-atmosphere – the most hotly debated plan for so-called solar radiation modification (SRM) – reverses a critical fraction of the sun’s rays as intended, the consequences could outweigh any benefits, they argue in an open letter.
“The deployment of solar geoengineering cannot be regulated globally in a fair, inclusive and efficient manner,” the letter said, backed up by a commentary in the journal WIREs Climate Change.
“Therefore, we call on governments, the United Nations and others to take immediate political action to prevent the normalization of solar geoengineering as a climate policy option.”
Temperatures rising 1.1 degrees Celsius above mid-19th century levels have already increased the intensity, frequency and duration of deadly heatwaves, droughts and megastorms.
Countries around the world have pledged to limit the rise in Earth’s surface temperature to 1.5C above mid-19th century levels, but UN-backed scientists have said the threshold will be passed, possibly within a decade.
The failure to cut greenhouse gas emissions, which are the cause of global warming, has led some politicians to embrace solar geoengineering, which not so long ago was considered more science fiction than science, to buy time to find a more sustainable solution.
It has long been known that introducing large amounts of reflective particles into the upper atmosphere can cool the planet.
Nature sometimes does this: the 1991 eruption of the Pinatubo volcano in the Philippines lowered the average surface temperature of the Earth by more than a year.
However, the open letter states that there are several reasons to reject this course of action.
Artificially reducing the radiative strength of the Sun is likely to disrupt monsoon rains in South Asia and West Africa and could destroy rainy crops on which hundreds of millions of people depend, several studies have shown.
“Stratospheric sulfate injections dampen summer monsoons in Africa and Asia and cause drought in the Amazon,” says the latest scientific assessment from the Intergovernmental Panel on Climate Change (IPCC).
However, other regions could benefit: a study was conducted last year that concluded that SRM could drastically reduce the risk of drought in southern Africa.
Scientists also fear a so-called “cessation shock” if the seeding of the atmosphere with particles blocking the Sun suddenly stops.
If SRM “is terminated for any reason, there is high confidence that surface temperatures will rise rapidly,” the IPCC said.
In addition, this technology will do nothing to stop the ongoing accumulation of CO2 in the atmosphere, which is literally changing the chemistry of the ocean.
The open letter also warns that hopes for a quick climate fix “could discourage governments, businesses and society from doing everything they can to achieve decarbonization or carbon neutrality as soon as possible.”
Finally, there is currently no global command and control system in place to control or implement solar geoengineering schemes that could be powered today by one country or even a billionaire with rockets.
The open letter called for an “international non-use agreement” that would block national funding, ban outdoor experimentation, and deny patent rights to SRM technologies.
Such an agreement “would not prohibit atmospheric or climate research as such,” the letter said.
Other forms of solar radiation modification include brightening sea clouds by seeding them with salt particles from the ocean and placing giant mirrors in space to reflect sunlight back to Earth.
Less controversial methods include bleaching house roofs and road surfaces, and lightening the color of crop leaves through genetic modification.
The open letter was signed by Frank Biermann, professor of global sustainability management at the University of Utrecht; Aarti Gupta, Professor of Global Environmental Governance at Wageningen University in the Netherlands; Professor Melissa Leach, Director of the Institute for Development Studies in Sussex, England; and Dirk Messner, President of the German Environmental Protection Agency.
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