Bangalore: Climate change studies have traditionally ignored the role of forests, which cover almost 30% of the earth’s surface. New research, however, shows that “forest dynamics” could dramatically alter the response of the global climate system to increased atmospheric carbon dioxide (CO2) over the years.
The research is featured in Friday’s issue of the journal Science, a special on forests. In the issue, scientists from all over the world focus on forests, which both influence and respond to the global climate, absorbing billions of tonnes of CO2 every year.
“Current climate models, for instance the ones that have been used to inform the latest Intergovernmental Panel on Climate Change report, do not include biology of any sort,” says Krishna AchutaRao, associate professor at the Centre for Atmospheric Sciences, Indian Institute of Technology in Delhi. They are what are called physical models and include only ‘land surface processes’, not counting vegetation in any meaningful manner, he adds.
The new research, by groups from Microsoft Research in Cambridge, the UK, and Princeton University in New Jersey, the US, used dynamic global vegetation models (DGVM) to establish the connection. The researchers, however, admit that since DGVMs are fairly new, they cannot be sure about their predictions—this makes vegetation dynamics one of the largest sources of uncertainty in Earth System Models.
Green connection: A forest survey report released by the government in February says India has lost only 0.11% of its forest cover since 2002. (Rajeev Dabral / Mint)
With all the CO2 that humans are putting into the atmosphere, Rao says it’s important to use these models to understand how the gas begins to affect the biosphere (plants, planktons, and all spaces that inhabit life). This is not only vital for the food chain, but will also determine how much of CO2 will stay in the atmosphere and how much can be absorbed by the biosphere.
There has been only some preliminary modelling of responses of Indian forests to climate change, says R. Sukumar, professor at the Centre for Ecological Sciences, Indian Institute of Science in Bangalore. He adds that there are several limitations to India’s modelling efforts and that the country needs more refined models that can predict changes at the regional scale as well as the responses of select species, such as teak or sal, to climate change. In one such study, reported in 2006, his group found that 75% of Indian forest types have the potential to change to another type because of climate change.
Earlier global studies have shown that such changes in land cover could lead to local temperature changes comparable with those caused by greenhouse gases. However, in his Science paper, Robin L. Chazdon from the University of Connecticut shows that while new forest plantations are being established globally, which will no doubt enhance biodiversity conservation, these will not match the composition and structure of the original forest cover.
This applies to India, too, where forests are highly fragmented and there’s no planned effort to monitor how species are changing over time.
“Could reforestation, perhaps with funding from the voluntary carbon markets, be planned in such a manner that we are able to achieve biodiversity conservation as well as restore the integrity of forest landscapes through providing corridors for the migration of plants and animals?” asks Sukumar.
According to the latest and most comprehensive survey—State of Forest Report-2005—which was released by the ministry of environment and forests in February, India has lost only 0.11% forest cover since 2002. It currently has 20.6% forest cover.
Not all forests are the same and just having a constant area says nothing about whether there is some species selection going on due to climate change that we are blissfully unaware of, argues AchutaRao. “It would be more important to know that the forests are stable ecosystems, and not just in areal extent.”
And it turns out the stability of forests also hinges on governance—how civil society and market incentives play their roles. Arun Agrawal from the University of Michigan and colleagues have taken a close look at the ownership of forests across the world and suggest a larger role for the community and market forces in forest governance.
“Market factors have affected forest governance in India from the very beginnings of British rule, and have historically been strong forces prompting (for the most part) deforestation,” says Agrawal. He believes market forces can work towards improved forest governance and outcomes only to the extent there is widespread awareness of the problem of deforestation and their sustainable use.
In this, he thinks, India has a long way ‘still to traverse’. “I am not convinced that the average Indian family will be willing to pay an extra Rs10 for a bundle of firewood.”
Forests cover 4 billion ha on earth, but are depleting at 7 million ha annually
India has planned afforestation of 1 million ha annually
China will increase its forests by 200 million ha, planting 4 million ha annually
Tropical forests are vulnerable to a warmer, drier climate, which will exacerbate global warming
Globally, governments own about 86% of the forests, private owners constitute 10% and community ownership is 4%