Since it unfortunately appears that CO2 emissions for the next several decades, at best will continue more or less constant, and at worst will increase, the obvious question is: If needed, could geoengineering offset the high CO2 greenhouse effect and return Earth's climate to its present state? The answer appears to be, yes, for the most part.......HOWEVER, potential adverse side effects of geoengineering are still unknown.
Following is a summary of the title link study led by Casper Ammann of the University Corporation for Atmospheric Research: "Results of the study show that a major, hypothetical geoengineering project, launched in the 2020s, could indeed return Earth’s mean surface temperature to the levels of 2000.
To achieve this, however, the tropics would need to be cooled below 2000 levels in order to offset the warming at higher latitudes. This is partly because the poles by the 2020s are projected to have lost so much sea ice, which reflects solar heat, that they would not be very sensitive to the impacts of geoengineering...... 'The changes in the Arctic may be so profound in the next couple decades that trying to ‘fix’ the climate there might turn out to be futile,' Ammann says."
Bottom-line: Even if we resort to geoengineering, and even if it works, it does not appear to be able to return Earth's climate back to the way it was in 2000 for ALL regions.
Since precipitation is a very important climate factor, Ban-Weiss and Caldeira of the Stanford looked at both global temperature and precipitation in response to sulfate aerosols, and compared optimizing one versus the other using a uniform and a parabolic (more at poles) aerosol distribution. Their results also show major improvements, but they too conclude that Earth's climate can not be engineered back to exactly as it was as long as CO2 levels remain high.
In the the last sentence of their abstract they add a further qualifier: "It is important to note that this idealized study represents a first attempt at optimizing the engineering of climate using a general circulation model; uncertainties are high and not all processes that are important in reality are modeled."
Conclusion: Geoengineering needs a LOT more research before it is considered as a serious option. Of course a rapidly deteriorating climate, with rising sea levels, more intense storms, more severe and widespread droughts, will spur on research and consideration.
Following is a summary of the title link study led by Casper Ammann of the University Corporation for Atmospheric Research: "Results of the study show that a major, hypothetical geoengineering project, launched in the 2020s, could indeed return Earth’s mean surface temperature to the levels of 2000.
To achieve this, however, the tropics would need to be cooled below 2000 levels in order to offset the warming at higher latitudes. This is partly because the poles by the 2020s are projected to have lost so much sea ice, which reflects solar heat, that they would not be very sensitive to the impacts of geoengineering...... 'The changes in the Arctic may be so profound in the next couple decades that trying to ‘fix’ the climate there might turn out to be futile,' Ammann says."
Bottom-line: Even if we resort to geoengineering, and even if it works, it does not appear to be able to return Earth's climate back to the way it was in 2000 for ALL regions.
Since precipitation is a very important climate factor, Ban-Weiss and Caldeira of the Stanford looked at both global temperature and precipitation in response to sulfate aerosols, and compared optimizing one versus the other using a uniform and a parabolic (more at poles) aerosol distribution. Their results also show major improvements, but they too conclude that Earth's climate can not be engineered back to exactly as it was as long as CO2 levels remain high.
In the the last sentence of their abstract they add a further qualifier: "It is important to note that this idealized study represents a first attempt at optimizing the engineering of climate using a general circulation model; uncertainties are high and not all processes that are important in reality are modeled."
Conclusion: Geoengineering needs a LOT more research before it is considered as a serious option. Of course a rapidly deteriorating climate, with rising sea levels, more intense storms, more severe and widespread droughts, will spur on research and consideration.
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