Scientists on planet Earth’s ‘Plan B’

In a New Year special, Britain’s The Independent asked 80 scientists what we can do to attempt to save the planet from the effects of global warming. The answers show diverging views on the effectiveness and safety of geo-engineering – man-made solutions devised to mitigate the effects of global warming.

The article is available in full here.

Some excerpts:

LuAnne Thompson, School of Oceanography, University of Washington

We are rolling the dice in a very dangerous way by assuming that we can introduce modification to alleviate problems that human kind has introduced to our environment. While in total, we have good predictions for the globally averaged changes expected from the increase of greenhouse gases in the atmosphere, we still have great difficulty in predicted local and regional changes. Determining whether a geoengineering solution would introduce mitigating changes in the weather is hubris. In addition, geoengineering solutions do nothing for the increasing pH in the ocean caused by the uptake of carbon dioxide by sea-water. If we choose to go the route of geoengineering, we are destining our children with a vastly changed ocean ecosystem. This will inevitably lead to a collapse of the remaining wild fisheries. In addition, the ocean’s ecosystem takes up carbon dioxide. By destroying the ocean’s ecosystem we will likely be introducing an addition source of carbon dioxide that would also need to be mitigated. Geoengineering is just not acceptable. The costs are far too high.

Anthony Patt, International Institute for Applied Systems Analysis

Geoengineering only solves some of the problems of climate change (e.g. arctic sea ice loss), but not others (e.g. ocean acidification, reduced diurnal and annual temperature cycle), and so it can never replace complete decarbonisation, but only complement it. With that in mind, it is an option to be considered, in parallel with other adaptation options.

With respect to a treaty to reduce carbon dioxide emissions, we must be open to the possibility that international negotiations will likely fail to stipulate the necessary emissions cuts. At the same time, subsidized investments in particular technologies (off-shore wind, concentrating solar power, combined with electrification of transport) could, if pursued aggressively by the US and EU over the next 10 – 15 years, push the costs for these technologies down to levels below that of coal, gas, and oil, making a global treaty unnecessary. (Indeed, this is why I am more optimistic now than 10 years ago about achieving the necessary emissions reductions).

Nick Brooks, visiting research fellow, Tyndall Centre for Climate Change Research

It is almost certain that we will fail to stop the globe warming by more than 2C, and probably more than 3C. All potential options for addressing climate change risks should therefore be considered. However, it would be foolish to focus on geoengineering options as a substitute for reducing greenhouse gas emissions. Geoengineering solutions do not help us avoid changes in the behaviour of the global climate system, but simply replace one kind of interference with another. While geoengineering may help reduce warming at the global level, it may still cause changes in atmospheric and oceanic circulation, particularly if it is targeted at certain regions or certain internal climatic mechanisms. Geoengineering also raises difficult ethical issues. For example, a geoengineering solution may reduce warming while resulting in regional changes in climate that adversely affect some parts of the world. Countries likely to suffer most from global warming may lobby for engineering solutions with adverse impacts on other countries. In the end, agreement over engineering solutions may be as difficult to achieve as agreement of emissions reduction targets. Mitigation of climate change through large and rapid reductions in greenhouse gas emissions remains the most reliable way of confronting anthropogenic climate change.