US President Joe Biden says "historic investment" is needed to deal with the climate crisis, as the north-east reels from flash flooding and tornadoes that have killed at least 41 people.

The US is facing climate-related destruction across the country and tackling it is "a matter of life and death", the president said.

New York City and New Jersey saw unprecedented levels of rainfall.

Some residents became trapped in flooded basements and cars.

Four states suffered loss of life:

• New Jersey Governor Phil Murphy said at least 23 people had died in his state - most of them stuck in their vehicles as the waters rose
• At least 14 people lost their lives in New York City, including a two-year-old boy. Eleven of them drowned while trapped in their flooded basements, officials said
• Three people died near Philadelphia, Pennsylvania, while one person was killed in Connecticut

The impact of climate change on the frequency of storms is still unclear, but we know that increased sea surface temperatures warm the air above and make more energy available to drive hurricanes, cyclones and typhoons. As a result, they are likely to be more intense with more extreme rainfall.

The world has already warmed by about 1.2C since the industrial era began and temperatures will keep rising unless governments around the world make steep cuts to emissions.