A new study by scientists in Germany has concluded that geo-engineering is unlikely to have anything more than a minor impact on global climate change.
Research conducted by scientists from the Helmholtz Centre for Ocean Research in Kiel, Germany, has concluded that even the most ambitious and large-scale forms of geo-engineering are unlikely to have much of a diminishing impact on global warming.
The study was led by oceanographer Dr. David Keller and published in the scientific journal Nature Communications. It looked at five forms of geo-engineering which have the potential to reduce the effects of global climate change, modelling the outcome of their deployment.
According to Keller, the study is one of the most thorough and comprehensive ever undertaken with respect to the real world impact of climate engineering.
"The problem with previous research was that in most cases the methods were studied with different models using different assumptions and different sets of earth components, making it difficult to compare the effects and side effects of different methods," he said. "We wanted to simulate different climate engineering methods using the same basic assumption and Earth system model."
The methods examined included the mass forestation of arid desert areas in North Africa and Australia, and the reduction of solar radiation levels via measures such as the sowing of aerosols in the atmosphere to produce artificial cloud cover.
Three of the methods entail tinkering with the earth's seas to raise their carbon dioxide uptake by means including the pumping of cold water rich in nutrients from the lower strata of the ocean; the sowing of iron to raise the fecundity of phytoplankton and thus foster the proliferation of plant life; and the dissemination of lime to increase CO2 absorption.
Despite the imaginative and ambitious nature of these geo-engineering methods, the study concluded that none of them are potent enough to significantly reduce levels of carbon dioxide in the atmosphere.
Even if they were deployed as early as the end of this decade, they would fail to make much of a difference given projected increases in the volume of greenhouse gases entering the atmosphere.
Modelling performed by the scientists concluded that the outcome for the earth's atmosphere remains the same irrespective of whether or not geo-engineering measures are implemented.
"Atmospheric CO2 continues to increase rapidly and still reaches more than twice the current levels by the end of the century in all simulations," said the study.
The methods would also have extreme ramifications for local ecosystems, given the radical nature and immense scale of any measures intended to influence the climate of the planet as a whole.
The mass forestation of deserts would "have a large and perturbing impact on local ecosystems and any societies that depend on them," while adding huge amounts of iron or lime to the sea would similarly impact ocean ecosystems, despite potentially conferring some benefits upon fish stocks.
Concurring with previous studies, the German researchers said that reducing solar radiation by tinkering with the atmosphere would stymie natural rainfall, as well as result in a rapid rise in temperature levels following the suspension of such measures.
The scientists said that while geo-engineering measures on their own would fail to serve as a panacea for the dilemma of global warming, they could still serve as a form of ancillary mitigation if their costs are below a reasonable threshold.