An international aid agency says changing rain patterns and rising temperatures in Nepal are leading to crop failures and increasing hunger.
Oxfam's country director Wayne Gum said in a report released Friday that impoverished farmers say crop yields had halved since last year.
This winter was Nepal's driest in 40 years.
Climate change experts predict rising temperatures will lead to less winter rain.
Experts say rising temperatures have also led to melting glaciers in the Himalayan mountains, which could lead to widespread droughts. The glaciers supply water for rivers stretching from Pakistan to Burma.
Oxfam's report comes ahead of a summit in Nepal of officials from across South Asia to discuss climate change.
Oxfam calls on international organizations and Nepal's government to raise awareness of the problem and develop strategies to address it, nationally and locally. It also calls on developed nations to do more to help.
Oxfam says Nepal is "extremely vulnerable to climate change," even though it only contributes a miniscule fraction -- 0.025% -- of the world's greenhouse gas emissions.
The U.N.'s World Food Program estimates more than 3.4 million people in Nepal require food assistance
Some information for this report was provided by AFP, AP and Reuters.