Science must drive ambition in Doha

The level of ambition at Doha, irrespective of how it is articulated has to be driven by scientific knowledge on anthropogenic climate change.

One of the major advances that has taken place over the last ten years or so is the gradual spread of awareness and knowledge related to this subject in different parts of the world.

Parties to the UNFCCC have decided on a review to be carried out during the period 2013-15 on its long-term global goal of limiting warming to below 2°C. The basis of the review would be largely IPCC's upcoming Fifth Assessment Report (AR5) and already observed impacts of climate change.

However, the IPCC has brought out three reports which already provide an adequate basis for initiating a review.

These three reports are the 2007 Fourth Assessment Report (AR4), and the Special Report on Renewable Energy Sources and Climate Change Mitigation (SRREN) as well as the Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX), both completed in 2011.

In the SREX it was clearly stated that economic losses from weather-and climate-related disasters have increased, but with large spatial and inter-annual variability.

Estimates of annual losses have ranged since 1980 from a few $ billion to above $200 billion (in 2010 $), with the highest value for 2005, which was the year of Hurricane Katrina.

However, loss estimates are lower bound estimates because many impacts such as loss of human lives, cultural heritage, and ecosystem services are difficult to value and monetize, and thus they are poorly reflected in estimates of losses.

The SREX clearly brought out the fact on the basis of certain scenarios, a 1-in-20 year hottest day is likely to become a 1-in-2 year event by the end of the 21st century in most regions.

The SREX also stated that it is likely that the frequency of heavy precipitation or the proportion of total rainfall from heavy falls will increase in the 21st century over many areas of the globe.

Earlier the AR4 had projected major impacts of climate change, such as increased water stress due to climate change and yields from rain-fed agriculture reducing by up to 50 per cent by 2020 on account of climate variability and climate change.

At the same time, actions required to mitigate the emissions of greenhouse gases are now attractive in technological and economic terms. For instance, the SRREN found significant increases in the dissemination and use of renewable energy technologies in recent years.

It also examined 164 different scenarios of contributions from renewable energy to the total energy supply, with the highest share being close to 80 % of the total energy supplied by 2050.

Overall, therefore, it is important for Doha to initiate the process of a review based on the robust and adequate scientific evidence already available.

This can be fine-tuned on the basis of the findings brought out in the AR5, which will be completed in October 2014.