Although coastal and freshwater wetlands – such as swamps, mangroves and marshes – contain 40 per cent of all plant and animal species, many are polluted or degraded due to climate change and human development.

On World Wetlands Day, observed this Thursday, the United Nations is calling for urgent action to revive and restore these ecosystems, which are disappearing three times faster than forests.

Wetlands cover roughly six per cent of the Earth’s land surface and are vital for human health, food supply, tourism and jobs.

More than a billion people worldwide depend on them for their livelihoods, while their shallow waters and abundant plant life support everything from insects to ducks to moose.

Wetlands also play a crucial role in both achieving sustainable development and in the fight against climate change.

They provide essential ecosystem services such as water regulation, reducing the impact of flooding, for example.

Peatlands, a particular type of vegetated wetland, store twice as much carbon as forests.

However, over the past 200 years, wetlands have been drained to make way for farmland or infrastructure development, according to the UN Environment Programme (UNEP).

Roughly 35 per cent of all wetlands globally disappeared between 1970 and 2015, and the rate of loss has been accelerating since the year 2000.

Depending on the amount of climate-related sea level rise, some 20 to 90 per cent of current coastal wetlands could be gone by the end of the century, UNEP warned.

Wetlands have also suffered more biodiversity loss than other land and marine ecosystems.