Dealing with hot air

Two major developments this month have brought the issue of human-induced climate change to the attention of the global community. The first was the release of the Intergovernmental Panel on Climate Change synthesis report (SR). The second, the agreement between the US and China to limit emissions of greenhouse gases (GHG) in both countries, reached after a prolonged period of quiet diplomacy between the two. The US-China agreement is an encouraging development that, it is expected, will motivate other countries to also make commitments to reduce GHG emissions. But as the findings of the SR clearly indicate, much more needs to be done to limit temperature increase to 2 degrees Celsius by the end of this century.

The SR, a document written for a non-specialist audience, released on November 2 in the presence of the UN Secretary General Ban Ki-moon, carries the essence of the major scientific-findings of the IPCC's recently completed working group reports, and two special reports dealing with renewable energy and extreme events and disasters, respectively. The 40-page summary for policymakers extracts the relevant essence of almost 7000 pages of published IPCC reports on which it is based.

This report updates our knowledge substantially on various aspects of climate change. For instance, it is stated with over 95 per cent confidence that human actions have been largely responsible for climate change since the middle of the last century. It also assesses scenarios for future climate change and related impacts, and finds that continued emission of GHGs will cause further warming and longlasting change in all components of the climate system, increasing the likelihood of severe, pervasive and irreversible impacts for people and ecosystems. Limiting climate change will require substantial and sustained reductions in GHG emissions which, together with adaptation, can limit climate change risks.

Surface temperature is projected to rise over the 21st century under all assessed emission scenarios. It is likely that heat waves will occur more often and last longer, and that extreme precipitation events will become more intense and frequent in many regions. The ocean will continue to warm and acidify, and the global mean sea level will continue to rise. Under this scenario, which is essentially based on inadequate mitigation efforts, the temperature increase could reach as high as 4.8 degrees Celsius and sea level 0.98 metre by the end of this century.

The Arctic region will continue to warm more rapidly than the global mean, and year-round reductions in Arctic sea ice are projected for all the scenarios assessed. A nearly ice-free Arctic Ocean in the summer, sea-ice minimum in September before the mid-century, is likely for the scenario based on inadequate mitigation efforts. The global mean sea-level rise will continue through the 21st century, likely at a faster rate than observed from 1971 to 2010. For the period 2081-2100 relative to 1986-2005, the rise will likely be in the range of 0.26 to 0.55 m, even for the scenario associated with stringent mitigation.

Sea-level rise will not be uniform across regions. This means that even if adequate mitigation efforts are made to limit the temperature increase to 2 degrees Celsius, the mean sea-level rise would lie in the range of 0.26 to 0.55 m by the end of the century. The average sea-level rise between 1900 and 2010 across the globe has been 19 cm. India, with a long coastline and several low-lying areas, needs to take this into account, as well as several other impacts of climate change. It is essential that adaptation efforts be taken in hand by identifying diverse impacts and strengthening local institutions and infrastructure where necessary, such that risks to life and property can be reduced. The severity of impact would require a diversity of suitable adaptation measures. For instance, an extreme precipitation event in the Himalayas could have devastating consequences. Climate change is also projected to affect agricultural yields, and this may require a variety of changes in cropping patterns, agricultural practices and other science-based responses.

Overall, adaptation alone will not help in meeting the challenge of climate change. Globally, the mitigation of emissions of GHGs will have to be addressed urgently and adequately. For India, it is important to remember that mitigation measures intersect with other societal goals, creating the possibility of co-benefits or adverse side effects. The identifiable co-benefits would be in the nature of higher levels of energy security, lower levels of pollution at the local level, higher agricultural yields, reduced threats to ecosystems and possible employment benefits. Near-term reduction in energy demand is an important element of cost-effective mitigation strategies, and there are several examples of co-benefits from measures such as changes in transport infrastructure, with greater reliance on public transport and better traffic management. Behaviour, lifestyle and culture have a considerable influence on energy use and associated emissions, with high mitigation potential in some sectors, in particular when complementing technological and structural change. Emissions can be substantially lowered through changes in consumption patterns, adoption of energy saving measures, dietary change and reduction in food waste.

India and the countries of South Asia in general are particularly vulnerable to climate change. It is also a fact that in several sectors of the economy with high energy intensity of production and consumption, India could get into a pattern of development that will not allow easy shifts in future, such as if our transport infrastructure grows on the basis of high energy intensity or our buildings are constructed with designs and building materials characterised by low efficiency levels of energy use.

The government of India has in place a National Action Plan on Climate Change (NAPCC), the implementation of which has been somewhat weak and ineffective. The time is perhaps ripe to revisit the NAPCC and put in place institutional measures by which plans are effectively implemented.

It would be appropriate to heed former US President Bill Clinton's opinion based on the SR. "This report makes clear: our climate is changing in longlasting ways that threaten ecosystems and growing numbers of people-yet, we still have the capacity to avoid the most dire predictions, by reducing emissions and changing the way we consume and produce energy. The actions that we need to take today must be commensurate with this profound threat to our way of life. The good news is those actions, properly implemented, will improve not weaken our economies, creating new jobs and businesses and lowering long-term energy and insurance costs for the rest of us."