KATHMANDU: With less than 50 days remaining for the Copenhagen climate change meet, environment activists all over the world have vowed to lower the concentration of carbon dioxide (C02), one of the main Green House Gases (GHG) to 350 parts per million (ppm) from the present 384 ppm. "The target 350 is safe landing point for the present condition. Predictably, if the CO2 level is decreased by 40 to 45 per cent by 2020, taking reference of the year 1990, the CO2 concentration will fall to 350 by 2050," said Dr Adarsha Pokharel, climate change expert.

According to 350.org, there were more than 4,500 programmes conducted simultaneously in 171 countries. Nepal was also a part of it. "We organised rallies, candle lighting ceremonies, climate walks and competitions across the country, in support of the 350 agenda," said Abhisekh Shrestha, a climate change activist. About 20 programmes were organised in support of 350 in Nepal. "Nepal does not play a crucial role in reducing emissions but we can fall victim to the hazards of climate change,” said Ganesh Shah, former environment minister.

Scientists agree that the safe upper limit for CO2 in the atmosphere is 350ppm. "Seventy per cent of the heat received from the sun is absorbed by the earth's surface, with only 30 per cent exiting from the GHG layer enveloping the earth. The GHGs such as CO2 enhance the blocking effect, trapping more heat in the atmosphere," said climate change expert Ngamindra Dahal. Global warming is taken as one of the major agents for climate change.

"GHGs are essential as well. Without them in the atmosphere, the earth's temperature will be minus 18 degree Celsius," said Dahal.