Evidence that climate change is causing or contributing to extreme weather events and natural disasters around the world is growing every day, threatening the lives and jobs of hundreds of millions of people, scientists and analysts said.

Dangerous heat waves surpassing 40 C are consuming large parts of the northern hemisphere, including the Indian subcontinent. In Australia's largest city Sydney, thousands were forced in recent days to flee floodwaters in and around the city for the second time this year.

Permafrost is melting in the Arctic, forest fires rage in Alaska, Europe is experiencing yet another heat wave, and glaciers are melting in the Italian Alps.

Such climate events, which in the past had been deemed "once in a lifetime", are now becoming regular occurrences.

As the world's climate changes, it is not only impacting where people live but also affecting food and water security. In Australia, experts are now urging governments from federal to the local levels to seriously reconsider urban development in flood－and fire-prone areas.

Jennifer McKay, a business law professor at the University of South Australia, said climate change and the risks that now come with it must be part of the decision-making process for urban development.

"We need a national Cabinet approach to this, guided by experts to set the standards," she said.

Otherwise, litigation will occur and insurance will be impossible to attain for people living in flood-prone areas of the country.

'Long-term resilience'

Piet Filet, a flood expert from the Australian Rivers Institute at Griffith University, said reducing the impact of floods in and around the Sydney Basin "will require a long-term resilience building program with communities in flood-prone catchments".

Filet said the history of flooding in Australia "not only reflects changing baselines in the frequency of extreme rainfall events, but also the need for key aspects of resilience building to be in place well in advance".

"Long-term land use planning that minimizes flood exposure is critical," he said. "Infrastructure in flood plains needs to be built to withstand the impact of fast flowing water and overcome the isolation of communities during floods."

It is a similar story around the world as countries battle natural disasters made worse by climate change.

Europe now faces one of its toughest years when it comes to natural disasters like droughts and wildfires because of increasing climate change. Stronger heat waves have hit southern and western Europe, as well as North America.

In Asia, an intense heat wave has gripped much of India in recent weeks, with temperatures hitting a record 49.2 C in parts of New Delhi, marking the fifth heat wave in the capital since March. Severe heat waves have thrown millions of lives and livelihoods out of gear in northern India this summer, with neighboring Pakistan also affected.