Interview With CHRIS RAPLEY On GLOBAL CLIMATE CHANGE

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Q & A : CHRIS RAPLEY Interview with CHRIS RAPLEY, president, Scientific Committee on Antarctic Research (SCAR) and director, British Antarctic Society ‘It is hard to imagine carbon as an illegal substance’ Posted online: Monday, June 04, 2007 at 0012 hours IST http://www.financialexpress.com/fe_full_story.php?content_id=166110 Considerable heat is being generated around the world in the debate on global climate change.

While scientists are assessing the impact of climate change, environmentalists are calling for its immediate mitigation and technologists are trying to find out newer means for adaptation. Concern is over the human activity inducing climate change and yet human activity is necessary for development. Therefore, a right balance is needed where development can go unhindered without disturbing the environment and ecology. On a recent visit to India to attend the 30th Antarctic Treaty consultative meeting in New Delhi, Chris Rapley, president of the Scientific Committee on Antarctic Research (SCAR), member of the International Polar Year 2007-08 Committee set up under the aeiges of the UN system and director of British Antarctic Society, analyses

the causes of climate change and finds its impact being acutely felt in the polar regions. In an interview with Ashok B Sharma, he urges all concerned to eliminate their disciplinary “silos” and work in an unprecedented manner to find out a “techno-optimist” solution. Excerpts: Is global warming a reality? First, we should understand our planet, Earth which is very complex, with its various components—atmosphere, ocean, ice, biosphere, humans and the solid earth—all interacting, with a myriad of interconnections, some highly

non-linear. Energy from the Sun is the predominant driver of all the activity, except the slow motions of the continents and processes in the planet’s interior. Geothermal heat, lunar tides and human energy generation are trivial in comparison. The balance between the energy intercepted and the energy radiated into space is almost same. Small differences cause the planet to warm or cool. The opacity of the atmosphere—mainly due to the presence of water vapour and carbon dioxide—to infra-red (heat) radiation from the Earth’s surface, which results in the atmosphere being warmed and in turn radiating some heat back to the surface. This phenomenon makes life on Earth possible. But by our emissions of carbon dioxide, we have enhanced the effect. The

upshot is an estimated current net imbalance between heat received by the surface and heat lost of approximately 1.5 W/m square. More than 90% of the total heat imbalance is absorbed by the oceans. The land surface warming of about 0.7 degree Celsius since pre-industrial times is due to both natural process and human-induced warming. Parts of the polar regions—Alaska, Siberia, Antarctic peninsula—have shown strongest increases in warming—up to five times the average. What is the contribution of burning of fossil fuel to global warming? It has caused increase in carbon dioxide in the atmosphere. Although the terrestrial biosphere (plants, trees and soil) and the oceans have assisted by absorbing roughly half of the emissions, the atmospheric carbon content has increased rapidly—a thousand times faster than the natural cycles of climate and carbon—and significantly by more than 35%, a magnitude equivalent to the natural variations between an ice age and an interglacial. There is a well-founded concern that in a warmer world, the terrestrial biosphere and oceans may become the sources rather than sinks for carbon. Geological process (rock weathering) by which carbon dioxide is removed from the atmosphere, operate on timescales too long to be relevant. The annual emissions of carbon due to human activity have risen from a few million metric tonne in 1850 to 7 Gigatons (GtC) today (the carbon dioxide tonnage 3.67 times greater). Direct measurements of carbon dioxide concentration in the atmosphere made since 1950s reveal that the current concentrations are greater than at any time over the past 860k years. The total amount of carbon injected is

estimated to be 500 GtC, with concentration of 320 GtC from carbon fuel burning and cement production and 180 GtC from land use change, mainly deforestation. What are your views on the report of the IPCC saying that the concentration of greenhouse gases far exceeds the levels of the last 650k years? The conclusions of the IPCC tend to be conservative. They are based on an evaluation of thousands of peer-reviewed scientific publications and have been agreed upon by the politically appointed delegates of 113

nations, including whose governments are climate sceptic. Over-exploitation of natural resources is another area of concern. The World Wildlife Fund’s Living Planet report indicates that the Human Ecological Footprint – the area of biologically productive land and water needed to provide the ecological resources and services used by humanity – exceeded the “one planet” threshold in mid-1980s. What are the threats caused by global warming? Most significant is the melting of glaciers, ice caps and consequent rise in the mean sea level which may ultimately lead to submergence of islands and vast land mass. Palaeco comparisons of global temperature and sea level show that whenever the world is warmer, sea levels rise. The summer sea ice cover in the Arctic has reduced by 25% over 30 years, impacting the ecology. The temperature warming of 2.5 degree Celsius in the Antarctic peninsula over the last 40 years has been the largest surface warming on the planet. It has caused nearly 90% of the glaciers to retreat and disintegrate a succession of ice shelfs.

Westerly winds have intensified and a hole in the ozone layer was seen.The 20 cm global sea level rise in last 100 years was due to the thermal expansion of seawater and the melting of mountain glaciers and minor ice caps. The collapse of Greenland’s southern ice dome and melting of West Antarctic ice sheet contributed to sea level rise. However the data from yet earlier warm periods suggest that the relationship between temperature and sea level is variable. Can we predict the mean sea level rise? Current numerical models are not capable

of predicting the speed or the nature of glacier retreat and water discharged to the seas. They suffer from numerical stability problems and do not contain “wet” ice dynamics—liquid water drainage beneath the ice sheet. However, a study shows that if the current levels of discharge were to continue, an ice volume equivalent to 1 to 1.5 m global sea level rise would be delivered to the ocean. The record of sea level rise since the end of the last Ice Age gives some insight, since it shows a sustained rate of sea level rise of 1 m per century over a 9,000 year period. Sea level rise was stable for the last 3,000 years, but has increased over the last century, initially to 20 cm per century. The present rate is 30 cm per century. What needs to be done? We need to eliminate disciplinary “silos” and work to understand the Earth. . There is no planetary “user manual” and the Earth is finite, without spares. It is difficult to imagine carbon being declared an illegal substance, but this is effectively what must happen sooner than later. The approach adopted to

arrest the depletion of stratospheric ozone caused due to human emissions of chlorofluorocarbons has worked. The other imperative is to find cost-effective and energy-effective means of sequestering carbon during its use and of “sucking” back carbon out of the atmosphere. A worrying fact is that over the last 7 years our carbon emissions have continued to be business as usual, deviating from the path of stabilizing it at 450 ppm. The bulk of the projected growth in human carbon emissions is attributed to the developing nations, which have a right to benefit in the way the developed nations have already benefited. There are significant issues of sharing between the developed and developing world and there is a major mismatch between the

jurisdiction, capabilities and motivations of existing institutions relative to what is needed. A proper global leadership is the need of the hour. I have attempted some approximate estimate for a “techno-optimist” solution for the cost of wedging carbon. The I GtC wedges from nuclear, wind energy and improved efficiency of cars would require an investment of $1-4 trillion. Since the world annual GDP is current $ 60 trillion, it seems affordable. The Stern report commissioned by the UK government says an investment of 1% of the GDP ($0.6 trillion) beginning now would avoid a future 20% economic downturn to be caused by climate change impact.

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