Geoengineering could disrupt rainfall patterns

Geoengineering could disrupt rainfall patterns
Volcanic eruptions, such as the one of the Karymsky volcano (Russia) in 2004, release sulphur dioxide to the atmosphere, which has a cooling effect. Geoengineering an ‘artificial volcano’ to mimic this release could be a solution to global warming, but one that may have undesirable effects for the Earth. Credit: Photo by Alexander Belousov of the Earth Observatory of Singapore, distributed by EGU via under a Creative Commons license.

A geoengineering solution to climate change could lead to significant rainfall reduction in Europe and North America, a team of European scientists concludes. The researchers studied how models of the Earth in a warm, CO2‑rich world respond to an artificial reduction in the amount of sunlight reaching the planet's surface. The study is published today in Earth System Dynamics, an Open Access journal of the European Geosciences Union (EGU).

Tackling change by reducing the solar radiation reaching our planet using , known also as geoengineering, could result in undesirable effects for the Earth and humankind. In particular, the work by the team of German, Norwegian, French, and UK scientists shows that disruption of global and regional patterns is likely in a geoengineered climate.

"Climate engineering cannot be seen as a substitute for a policy pathway of mitigating climate change through the reduction of greenhouse gas emissions," they conclude in the paper.

Geoengineering techniques to reduce the amount of solar radiation reaching the Earth's surface range from mimicking the effects of large volcanic eruptions by releasing sulphur dioxide into the atmosphere to deploying giant mirrors in space. Scientists have proposed these sunlight-reflecting solutions as last-ditch attempts to halt global warming.

But what would such an engineered climate be like?

To answer this question, the researchers studied how four models respond to climate engineering under a specific scenario. This hypothetical scenario assumes a world with a CO2 concentration that is four times higher than preindustrial levels, but where the extra heat caused by such an increase is balanced by a reduction of radiation we receive from the Sun.

"A quadrupling of is at the upper end, but still in the range of what is considered possible at the end of the 21st century," says Hauke Schmidt, researcher at the Max Planck Institute for Meteorology in Germany and lead author of the paper.

Under the scenario studied, rainfall strongly decreases – by about 15 percent (some 100 millimetres of rain per year) of preindustrial precipitation values – in large areas of and northern Eurasia. Over central South America, all models show a decrease in rainfall that reaches more than 20 percent in parts of the Amazon region. Other tropical regions see similar changes, both negative and positive. Overall, global rainfall is reduced by about five percent on average in all four models studied.

"The impacts of these changes are yet to be addressed, but the main message is that the climate produced by geoengineering is different to any earlier climate even if the global mean temperature of an earlier climate might be reproduced," says Schmidt.

The authors note that the scenario studied is not intended to be realistic for a potential future application of climate engineering. But the experiment allows the researchers to clearly identify and compare basic responses of the Earth's climate to geoengineering, laying the groundwork for more detailed future studies.

"This study is the first clean comparison of different models following a strict simulation protocol, allowing us to estimate the robustness of the results. Additionally we are using the newest breed of climate models, the ones that will provide results for the Fifth IPCC [Intergovernmental Panel on ] Report," explains Schmidt.

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Citation: Geoengineering could disrupt rainfall patterns (2012, June 6) retrieved 20 July 2019 from
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Jun 06, 2012
- Mimic the Dimethyl Sulfide mechanic.
- Seed marine algae with nutrients

Jun 06, 2012
Do we honestly think we can predict with 100% realiablity the impact and risks and long term effect of any method of artificial climate change.

The smartest thing we can do is work to be smart about how we use our resources, continue to work towards a more effecient model and adapt to changes the earth is going to make with or without our input.

Jun 06, 2012
Geoengineering is a bad idea whose time is never. "So we don't really know how the whole engine works, but let's just go ahead anyway and push a few buttons here and there, and maybe . . OOPS - run, run for your lives!"

Jun 06, 2012
I just had a flashback to the final episode of the old tv show "Dinosaurs".

The earth is a very complex system and we don't know nearly enough about how it works. This sort of thing strikes me as a spectacularly bad idea.

Jun 06, 2012
We are alrady in the middle of a giant experiment of altering climate.

We might possibly try Geoengineering Lite, regionally blocking a fraction of the sunlight hitting the Arctic region. That might slow the melting of the ice, and maybe slow the thawing out of the permafrost.
-Since the permafrost traps *a lot* of methane -a powerful greenhouse gas- it might be worth some minor rainfall re-distribution to stop this from happening!

Jun 07, 2012
We are alrady in the middle of a giant experiment of altering climate.

And we really are doing a great, aren't we? To the point where we ignored, then completely misjudged, and now willfully ignore the ramifications.

This does not bode well for geoengineering. Even geoengineering lite.

This should be general rule: Don't bet your life (and especially that of others) on something that you cannot undo if it goes south

Jun 07, 2012
Geoengineering could disrupt rainfall patterns

Ya think? On the other hand, defining "geoengineering" broadly enough, "disrupt" might be the wrong term here. After all, virtually every last lake in Texas is man-made (there is a single quasi-exception), the results of which have "disrupted" rainfall patterns in a very beneficial way.

Of course, we also needed the lakes. Their creation addressed numerous real problems.

A geoengineering solution to climate change...

On the other hand, a geoengineering solution to a non-existent problem is most assuredly a titanically horrible idea.

Jun 07, 2012

This does not bode well for geoengineering. Even geoengineering lite.


Jun 07, 2012
I am pretty sure they are doing it in the EU as well, they just like to keep it quiet.

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