The devil of climate change is making home in god's own country. Concerns range from its impact on rain-fed agriculture to lifestyles of coastal communities, from the region's biodiversity in general to the shrinking of ecosystems in the Western Ghats.

"Perhaps the best examples of plants shifting their flowering season and birds altering their breeding patterns are the konna flowers and the drongo,'' says V S Vijayan, chairman of the Kerala Biodiversity Board. "Earlier they used to flower in April, in time for Vishu. But last year, the trees flowered in October and the flowers were lost before Vishu," recounts the noted scientist who led an agitation against a hydro-electric project in Silent Valley in the state's north.

"The signs are also showing in the drongo's behaviour. The insectivorous birds used to have their eggs hatched by February-March , but now they do it much earlier, in accordance with the change," Vijayan points out.

A study conducted by the Kochi-based Central Marine Fisheries Research Institute (CMFRI) has also shown different marine species reacting to the rising heat. "The state's coasts were abundant with oil sardines that require warm temperatures for spawning. Now we notice that their spawning area has increased up to the Maharashtra and Orissa coasts, indicating rising temperature in the water there," says E Vivekanandan , principal scientist and head of the Demersal Fisheries Division at CMFRI.

Another instance, he says, is the shift in the spawning season of at least two varieties of threadfin bream (kili meen) to the cooler months of October to March. "This is because the average temperature in the seawater has risen by 0.3°C in the last 15 years. It could go up by another 2.5°C by the end of the century.''

In Chennai, where monsoon season flooding and drinking water availability during summer are perennial concerns, the changing pattern of rainfall is already causing anxiety. "The rains will be short and intense in future. Administrators will have to evolve new models for flood mitigation," Prof Ram Ramanathan, a renowned climatologist , had said soon after several parts of the southern metro were inundated during last year's monsoon.

Scientists from Tamil Nadu working on climate change are convinced rainfall patterns have perceptibly changed: heavy downpours for a few days replacing the usual rains spread over months. "New approaches will have to be evolved in cities, coastal areas and in the deltas as well," says Professor Ramanathan, a distinguished professor of climate and atmospheric science.

"Changes induced by climate change can be noticed along the coast. There is a loss of habitat and bio-diversity in coastal areas,'' says Prof R Ramesh, director, Institute for Ocean Management, Anna University. His team of researchers has noticed increased concentration of carbon dioxide, methane and nitrous oxide, but the sea level has not risen as seen off the Bengal or Bangladesh coasts.

Apart from climate change, human-induced pressure has also contributed equally to these changes, Ramesh says. While the density of population in Tamil Nadu's coast is 1,000 per sq km, it is 40 or 50 per sq km in most nations, he notes, adding that the higher methane presence is due to heavier sewage flow into the coastal waters.

Cultivation patterns have changed along the Western Ghats as deforestation is taking its toll. Plantations in forest areas have led to soil becoming loose, triggering landslides.

Resurfacing of diseases like chikungunya is being linked to climate change too. The virus breeds and becomes virulent due to the extended warmer season (just like mosquitoes storming Darjeeling and malaria catching up with Himachal Pradesh), says E Ramji, scientist in-charge , Centre for Environmental Education (CEE), Tamil Nadu.

Funded by Norway, ClimaRice is an integrated approach underway in Cauvery delta to assess sensitivity of the rice eco-system to climate change. While the International Pacific Research Centre at Hawaii uses high resolution regional climate models to understand future impacts on monsoon and frequency and intensity of drought in the study area, the Tamil Nadu Agricultural University will develop hydrological and crop weather modelling.

In Karnataka, where 80 per cent of agriculture is rain-fed , the impact of climate change on the Western Ghats has got experts into thinking of an action plan that can adapt to the socio-economic and environmental consequences. The Energy and Resources Institute (TERI) has proposed to the Karnataka government a "vulnerability study" of agriculture , coastal communities and biodiversity.