A climate study predicts a big rise in temperature across India's picturesque Northeast.

The charms of some of India's most scenic mountain valleys, especially those in the Northeast, may be set to fade. Climate scientists have recently confirmed what hill communities have long been saying: that climate change is impacting the North-Eastern states.

Recent findings show that changing climate patterns will affect the picturesque region in several ways. The most obvious one - assessed by analysing temperature data over the last 35 years from 11 meteorological stations in seven states across the region - is an increase in the occurrence of 'warm nights'. This trend is likely to worsen, according to computerbased climate models that were used to predict future climate trends. According to recent research exercises conducted by the Centre for Atmospheric Sciences at IIT Delhi, there has even been a rise of about two degrees, huge by climate change standards, in the average night-time temperature between 1971 and 2005. The annual mean temperature over northeast India also displays a markedly upward trend: up 0. 04 degree C per year, which means a big rise of 1. 4 degrees in 35 years.

There may be a 5. 15 degree C rise in annual mean surface temperature by the end of this century, says the study, titled 'Temperature and Precipitation Changes in Northeast India and their Future Projections. It was published in the December 2012 edition of the highly regarded journal, Global And Planetary Change.

But considering the volatile politics of climate change, based in large part on many people questioning large-scale assumptions in several studies, just how reliable are these predictions? The study's lead author, S K Dash of the Centre for Atmospheric Sciences, IIT Delhi, says that model projections do have some uncertainties. Yet the model used for this particular climate projection, RegCME3 in boffin-speak, was able to predict "recent past" climate over the region reasonably well, says Dash. "We correlated the results from the model with IMD data from 11 weather stations and found that it was good. Hence, the inference that the model will project the future more or less correctly, " he says.

An increase in the frequency and intensity of 'warm nights' doesn't just mean discomfort for local communities used to temperatures that range from cool to cold after sunset over the course of the year. Such warming has far more serious ramifications. As Dash puts it, "We haven't assessed the impact of warm events on biodiversity. But we can say that the ecosystem, including the glaciers in the region, could be affected by the temperature rise. "

Communities in northeastern states are realising what the fallout of such change means, but in different ways. "The fact that the temperature is increasing is being felt for the past two decades. But the trends vary in different regions. I think the impact is slightly more intense in the Northeast than other parts of the country. Even though there are several scientific studies based on different computer models, their predictions are different from each other. The community though, has a consensus on certain trends that they are experiencing, " says Partha J Das of Aranyak, an environmental NGO in Guwahati.

Three trends are clear: an overall warming across all seasons;heat waves in summer;and shrinking winters. "Winter used to last from November to February till a few decades ago. Now it has shrunk to just 60 to 70 days in December and January, " says Das.

In Meghalaya, for one, such climate change is gradually being registered. B K Tiwari of the Northeastern Hill University conducted a study on people's perception of climate change in the region a few years ago. "But the responses were not conclusive. There was a consensus only on one aspect: most people agreed that extreme weather events like floods have become more frequent. But these perceptions have no scientific backing. They are just people's assessments. So, I think relying on IMD data of at least 30 years is a more practical method of understanding climate change, " he says.

In many parts of scenic Sikkim, local communities are experiencing a clear shift in climate. The breeding of mosquitoes at relatively high altitudes is one symptom, according to Karma Tenpa, a hotelier from North Sikkim. "Villagers know that the climate is not the same anymore. Mosquitoes have started breeding in high altitude towns like Tumlong. My parents say there were no mosquitoes when they were young. But I am not sure whether they have felt small changes like warmer nights, " he says.

Karma also talks of how most of Sikkim's residents have an intrinsic relationship with the verdant ecology of the region, on account of their religious beliefs. "The hills, stones, streams - almost every aspect of nature is worshipped here. The community naturally is sensitive to any change in our ecology. "