New taxes on air travel and maritime shipping could raise the billions of dollars needed to help the countries suffering most from climate change, a UN expert said Friday.

"Such levies, based on the well-established polluter-pays principle, could raise hundreds of billions of dollars annually to assist small island developing states (SIDS) and least developed countries (LDCs) recover and rebuild from the damage caused by climate change," said David Boyd, UN special rapporteur on human rights and the environment.

The climate crisis is also a human rights crisis, he said in a message directed at world leaders gathering in the UK's Glasgow for the UN Climate Change Conference (COP26) that starts Sunday.

"People living on these small islands and at least developed countries are already suffering devastating losses and damage from climate change – more frequent extreme weather events, floods, droughts, rising sea levels, and saltwater contamination of their water supplies and agricultural lands."

Read: EU lauds Bangladesh’s leadership on climate front

In recent years, powerful hurricanes and cyclones have wreaked havoc on the Bahamas, Dominica, Fiji, Vanuatu and other countries, damaging up to 90 per cent of buildings and inflicting losses that sometimes exceeded their annual GDPs.

Over the past three decades, wealthy states have failed to provide virtually any funds for vulnerable countries to deal with loss and damage caused by climate change, which will rise to $290 billion to $580 billion every year by 2030.

Boyd elaborated his proposals in a brief to the COP26 leaders in which he analysed two innovative financing approaches proposed by the Maldives, the Republic of Marshall Islands and Solomon Islands.

Taxes on commercial aviation and maritime shipping would be fair because these sectors are major polluters, with combined emissions larger than some of the biggest emitters of greenhouse gases, he said.

Read: COP26 president-designate visited Bangladesh to see climate crisis firsthand

Emissions from these sectors have grown rapidly in recent decades and are projected to more than double by 2050.

COP26 should be a turning point in global efforts to develop new and innovative sources of climate finance to address losses, damages, and adaptation, with a particular focus on the needs of the SIDS and LDCs, the UN special rapporteur on human rights and the environment said.

"The time for talking about support for climate-vulnerable countries is long past," he added. "Now is the time for urgent action."