Emissions of greenhouse gases (GHGs), of which CO2 is the most dominant, have been growing rapidly in recent decades. Between 1970 and 2004, GHG emissions as a whole increased by 70 per cent and carbon dioxide 80 per cent.

The Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC) clearly stated, “Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice and rising global average sea level.”

It also stated further that most of the observed increase in global average temperatures since the mid-twentieth century is very likely due to the observed increase in anthropogenic GHG concentrations. In this context the term “very likely” denotes a probability of over 90 per cent.

The impact of climate change is now being observed across the globe and has significant implications for availability of water, for human health and the preservation of a large variety of living species.

Climate change also impacts agriculture, and as a result of melting of ice across the globe as well as thermal expansion of the oceans, rise in sea level is taking place worldwide threatening, in particular, small island states and low lying coastal areas.

Difficult to monetise

More recently, the IPCC’s Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation came up with several findings which require attention from all stakeholders in society, including government, business, civil society, research and academic institutions, and most importantly, the media.

Among the various findings of this report, some are of significance to different parts of the world but of particular concern to India.

For instance, economic losses from weather- and climate-related disasters have increased, but with large spatial and inter-annual variability. Global weather- and climate-related disaster losses reported over the last few decades reflect mainly monetised direct damages to assets, and are unequally distributed.

Estimates of annual losses have ranged since 1980 from a few billions of dollars to over $200 billion in 2010, with the highest value for 2005 (the year of hurricane Katrina).

Loss estimates are on the lower side because many aspects of impact, such as loss of human lives, cultural heritage, and ecosystem services, are difficult to value and monetise and thus they are poorly reflected in estimates of losses.

The impact on the informal or undocumented economy as well as indirect economic effects can be very important in some areas and sectors, but is generally not counted in reported estimates of losses.

During the period from 1970 to 2008, over 95 per cent of deaths from natural disasters occurred in developing countries.

Extreme swings on cards

As for projections of such extreme events and disasters, some have particular relevance to India. Models project substantial warming in temperature extremes by the end of the 21st century. It is virtually certain that increases in the frequency and magnitude of daily temperature extremes and decreases in cold extremes will occur on a global scale.

It is very likely that the length, frequency, and/or intensity of warm spells or heat waves will increase over most land areas. Based on certain emissions scenarios, a one-in-twenty-years hottest day is likely to become a one-in-two-years event by the end of the 21st century in most regions, except in the high latitudes of the Northern Hemisphere, where it is likely to become a one-in-five-years event.

Further, 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.

This is particularly the case in the high latitudes and tropical regions, and in winter in the northern mid-latitudes. Heavy rainfall associated with tropical cyclones is likely to increase with continued warming. Also, it is very likely that a rise in mean sea level will contribute to upward trends in coastal water levels in the future, affecting, as mentioned earlier, low-lying coastal areas and small island states across the world.

All these implications of climate change, both current and projected, require adaptation measures, so that risks to life and property can be minimised.

These measures are included in India’s National Action on Climate Change but their effectiveness would require institutional capacity being developed and implementation taking place at the level of State governments and at the local level as well. There are many approaches and pathways to a sustainable and resilient future.

However, limits to resilience are faced when thresholds or tipping points associated with social and/or natural systems are exceeded. Hence, an effective strategy for dealing with climate change would require mitigation of emissions of GHGs at the global level and adaptation involving all stakeholders across the spectrum in every nation and every community.