Donnerstag, 8. Mai 2014

IPCC changes its tune on gas as way to mitigate climate change

● By Prof. Janusz Bialek, Durham University ● 

The International Panel on Climate Change’s Working Group 3 report is a welcome outline of how to stem the tide of climate change. It illustrates a significant change in strategy, from a complete switch away from fossil fuels to other mitigation measures.

Until recently IPCC strongly advocated switching away from fossil fuels as the main route to carbon neutrality. Any mention of other mitigation measures tended to be dismissed as defeatist and diverting attention from the real problem of switching away from fossil fuels.

But recent developments seem to have forced the IPCC to change its tack. The innovations and reforms laid out to reduce emissions include short-term measures such as switching from coal to gas, as well as the loftier goal of turning to renewable energy.

Global effort

Preventing global warming requires a concerted effort of the whole world – it therefore requires agreement of all the governments. This has proved to be impossible to achieve, despite numerous world summits. Perhaps this kind of global cooperation was rather naïve to hope for. The lack of consensus, however, has meant that global greenhouse gas emissions continue to rise. This makes keeping temperatures to a 2°C increase more and more difficult.

The world financial crisis of 2008 and the recession it caused has highlighted the cost of switching away from fossil fuels. The expense of a switch would jeopardise global economic recovery and increase “fuel poverty”, or indeed lack of access to electricity, by making electricity more expensive.

It is noted that “about 1.3 billion people worldwide do not have access to electricity and about 3 billion are dependent on traditional solid fuels for cooking and heating with severe adverse effects on health, ecosystems and development”. Responding to financial pressures, subsidies for renewables have been reduced in many countries over the last few years making investment in them less profitable.

Golden age of gas

The perceived depletion of fossil fuels globally was one of the additional reasons for the IPCC previously advocating a switch away from fossil fuels. But the shale gas revolution in the US and the growth of unconventional hydrocarbons has shown that oil and gas reservoirs are far from extinct. Indeed, the International Energy Agency’s World Energy Outlook report for 2011 spoke of the “Golden Age of Gas”.

An abundance of cheap gas not only puts severe competitive pressure on renewables and nuclear, it also offers a short-term bridge to a low carbon future, as producing electricity from gas gives of about half the CO2 emissions of coal. As coal is still a dominant fuel source in many countries in the world – notably in China and India – switching to gas would reduce their CO2 emissions considerably and at much lower costs than switching to renewables, as it did in USA.

Despite the US government failing to act convincingly on climate change, America has achieved some of the highest reductions of CO2 emissions in recent years thanks to the switch from coal to gas.

Lesser of two evils

Environmentalists have previously dismissed the argument for investing in gas, for fear it would lock us into a high-carbon future (when compared to switching to renewables). But the latest IPCC report seems to accept the gas argument by saying:

Greenhouse gas emissions from energy supply can be reduced significantly by replacing current world average coal‐fired power plants with modern, highly efficient natural gas combined‐cycle power plants or combined heat and power plants, provided that natural gas is available and the fugitive emissions associated with extraction and supply are low or mitigated (robust evidence, high agreement).

This is a welcome departure from a principled but very expensive and therefore unrealistic position of dismissing gas to a more realistic one of accepting it as a cheaper “lesser evil”. In fact, gas power stations, due to their ability to change generation relatively quickly, play an important role in providing a flexible back-up for intermittent wind and solar generation in many countries (such as Ireland).

What about nuclear?

Nuclear was previously seen as an important low-carbon technology. But the Fukushima disaster has caused many countries in the world, most notably Germany and Japan, to abandon nuclear energy. As a result Germany, despite very significant advances in deploying wind and solar energy, has increased its CO2 emissions due to replacing nuclear partially by coal and lignite – the two worst carbon polluters.

The latest report therefore recommends that nuclear power can make an “increasing contribution to low-carbon energy supply”, though this is not without its ill-effects on the environment. It also goes to show why there is more emphasis on gas as a short-term bridge in the latest report.

Action now

There is increased appreciation that it is more important to take action now rather than later to prevent further accumulation of greenhouse gases in atmosphere. This is why the short-term and effective – albeit imperfect – mitigation measures, such as switching from coal to gas, are better than long-term perfect ones, such as switching to renewables. By the time the latter are established to be more cost-effective, it might be too late to prevent climate change.

The IPCC report shows there are a variety of different ways to mitigate against climate change. Apart from the usual call to increase the uptake of renewables, they advocate replacing coal with gas, deploying carbon capture and storage, technical and behavioural changes for all modes of transport, reducing fuels that are carbon intense and the building sector’s use of energy, as well as generally improving energy efficiency across sectors. Continued efforts must be made across the world to implement these more realistic measures.


LEXEGESE Editor's Note: Janusz Bialek receives funding from Engineering and Physical Sciences Research Council. This article was originally published on The Conversation. Read the original article.

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