A growing global push to safeguard nature by pledging to protect about a third of the planet's land and oceans by 2030 will fall short of that goal unless biodiversity-rich Southeast Asian nations get behind the ambitious proposal, environmentalists have warned.

This month, leaders of the G7 wealthy nations backed a coalition of about 60 countries that have already promised to conserve at least 30% of their land and oceans by 2030 (30x30) to curb climate change and the loss of plant and animal species.

Cambodia is the only Southeast Asian nation to have signed up to the goal so far, although it has been endorsed by countries in other parts of the Asia-Pacific region, including Japan, Pakistan and the Maldives.