Sweltering under the record temperatures of a blistering hot spring, Pakistan's farmers have this year had a vivid glimpse of the dangers a changing climate many pose to their livelihoods.

As summer's fierce heat this year arrived weeks early, the mercury rose above 50C (122F) and set what is thought to be a world record for an April temperature.

The scorching weather of 2018 follows a trend of increasingly short, warm and early spring seasons which have left Pakistan's farmers struggling to deal with new weather patterns.

The heat has dried out farmland and hit profits by causing fruit and vegetables to ripen earlier, but smaller.

New research from the World Bank attempting to quantify how climate change will affect South Asia over the coming decades has now warned weather changes risk badly denting the living standards of hundreds of millions in the region.