Weather disasters in Malawi and Pakistan have worsened health conditions, causing a surge in cases of diseases such as malaria, according to Peter Sands, the head of the Global Fund to Fight AIDS, Tuberculosis and Malaria.

In both Pakistan and Malawi, the pools of water left after the waters have receded are an ideal breeding ground for the mosquitoes that carry the disease. Infections in Pakistan quadrupled after devastating floods in the country last year, reaching 1.6 million cases, according to the World Health Organisation (WHO); and a rise in malaria cases was seen in Malawi after Cyclone Freddy wreaked havoc in March, bringing the equivalent of six months' rainfall to the small East African country.

By 2021, the WHO estimated that there would be 247 million cases worldwide. Some 619,000 people died of malaria that year. But this year there is a need to "sound the alarm", he says. "If malaria is getting worse because of climate change, we need to act now to roll back (the disease) and eliminate it.

Sands said there has been progress in the fight against malaria, but that a child dies of the disease every minute.