Climate variability and risks have always been a part of agriculture, due to which farmers have developed many ways of managing risks. Searching and exchanging drought-resistant seeds and other abiotic stress-tolerant crop varieties and adopting and practicing specific soil and water management practices for marginal areas have long been core activities of the farming communities. Climate change introduces a new dimension to the problem. The unprecedented rate and magnitude of climate change presents great challenges to farmers, researchers and policymakers a like and all need to collaborate at local level to address this problem. There is abundant scientific evidence that agrobiodiversity has an important role to play in ensuring the adaptation needed to maintain production.

In South Asian countries, particularly India, Nepal and Bangladesh, farmers are already adapting to changing conditions by using traditional seed exchange practices that are part of established seed systems. Farmers can also use their knowledge of abiotic stress tolerance and adaptability in their materials and work with plantbreeders to develop varieties that are adapted to changing local conditions andpossess improved yields and quality (Jarvis et al, 2007). Many adaptation practices involving crops and livestock have been reported (e.g. Reid and Swiderska, 2008). Traditional farming system management practices and farmers? innovations are clearly a key element in local adaptation to climate change. While scientists and policymakers work to find solutions, local farmers have already amassed considerable experience of how to cope, based on their observation and experimentation in the field (Reid and Swiderska, 2008). A comparative study (Bhandari, 2009) of hill and Terai agroecosystems found that more households (40%) in the Terai rather than in the hills (11.6%) reported production decreases (of 5-25%) due to abnormal rainfall. It has been suggested that the continuing richness of traditional varieties in the hills places an important part in explaining this difference. A higher risk of food insecurity during abnormal rainfall years in the Terai has also been noted due, perhaps, to vulnerability of modern varieties. Through farming practices farmers are able to keep traditional varietiesadapted to changing growing conditions and social preferences. The varieties are open, dynamic genetic systems constituting metapopulations whose genetic constitution reflects both natural and human seed selection.

The importance of maintaining a portfolio of crop varieties was demonstrated recently in the Western Terai Landscape Complex Project. Farmers in the Kanchanpur districthad lost their local landraces of rice because they prioritised high yielding early maturing varieties. The project made available traditional local varieties, such as Tilki and Shyamjeera, and these were found to survive flooding caused by a major flooding in October 2008, which caused widespread destruction and some loss of life. A very short duration local rice variety, Sauthariya, has also been shown to be useful and is planted when other varieties fail as a result of drought.