Global warming is causing "massive problems" for Nepal, melting snows and bringing deadly floods despite the Himalayan country's low greenhouse gas output, a minister said on Thursday.

The towering mountain range that forms Nepal's northern border with Tibet is showing worrying evidence of global warming, Environment Minister Formullah Mansoor told AFP.

"Our contribution is very low in the global context, but the effects of global warming on our country are very high and costly," the minister said.

"Climate change is causing Nepal massive problems like rapid snow-melting, glacial lake outbursts and resulting deadly floods," said Mansoor who issued a statement highlighting climate change in Nepal to mark World Environment Day.

Other problems include "receding snow lines, too much rainfall, haphazard weather patterns that could result in flash floods and drought," he said.

The minister's comments came after avid mountaineer Apa Sherpa, who last month climbed the Mount Everest for a record 18th time, said his latest climb was to highlight the effects of climate change in the Himalayas.

Apa said he had seen first-hand the dangers wrought by fragile, melting ice.

In addition, climbers have been reporting the steady break-up of the Khumbu icefall, a treacherous maze of cliffs and crevasses that guard the southern approach to the 8,848-metre (29,028-feet) peak.

The glaciers and snow of the 4,000-kilometre (2,500-mile) Himalayan range that spreads from Afghanistan in the west to Myanmar in the east is the world's biggest reserve of ice outside the polar regions.

The Himalayan range is the source of several major Asian rivers that support millions of people downstream, including the Ganges, the Brahmaputra, the Irawaddy, the Mekong and Yellow River.