Amid fresh warnings about the depletion of Earth's treasure trove of species, governments will gather in South Korea next week to try to muster the funds and political will to protect what remains.

Just a week after conservation group WWF said wildlife numbers had halved in 40 years, nations will analyse progress since they agreed four years ago on 20 targets for stemming the tide of biodiversity loss.

Parties to the Convention of Biological Diversity (CBD) will meet for 11 days from Monday in Pyeongchang to thrash out a roadmap for achieving the "Aichi Targets" -- which include halving habitat loss, reducing pollution and overfishing, and putting a brake on species extinction by 2020.

And once again nations will embark on the difficult task of trying to determine how much money is required and where it will come from.

"This meeting is the halfway stock-take: where are we in terms of achieving the targets and what extra effort, what extra momentum, what horsepower we need to get there by 2020?" WWF policy director Susan Brown said.

"And so we look at some of the barriers and stumbling blocks and... do countries actually have the resources, the financial mobilisation?"

For many, the answer is a blunt "No".

"Many of the targets the world agreed on will not be met in time," International Union for Conservation of Nature (IUCN) Director General Julia Marton-Lefevre told AFP.

"We can't overstate the need for governments to intensify their efforts and resources for the sake of nature and the well-being of their people. This is the best investment we can and must make to ensure a sustainable future for all."

- Species peril -

The most recent update of the IUCN's Red List of threatened species in July said a quarter of mammals, over a tenth of birds, and 41 percent of amphibians are at risk of extinction.

Last week, the WWF's 2014 Living Planet Report highlighted a 52-percent decline in mammals, birds, reptiles, amphibians and fish overall from 1970 to 2010.

It said humans were consuming resources at a rate that would require 1.5 Earths to sustain -- gobbling up animal, plant and other resources at a faster rate than nature can replenish them.

In a bid to arrest the decline, nations agreed on the 2011-2020 Aichi Targets at a meeting in Nagoya, Japan, in 2010.

But they have struggled to find common ground on funding, especially for poor nations whose scarce resources are already committed elsewhere.

At the CBD's last meeting, in Hyderabad, India, in 2012, the world agreed to double biodiversity aid to developing countries by 2015.

But they did not quantify either the base amount or the target -- and the numbers are still far from being resolved.

"Not much has happened in the last two years," said Maggie Comstock, senior manager for finance policy at green group Conservation International.

"Obviously, every year that we delay in the finance and making (of) these investments only means more loss of biological diversity but also making future conservation more unattainable."

European Environment Commissioner Janez Potocnik told AFP the EU would "live up to the commitments on resource mobilisation" that were made in Hyderabad, but also "hopes to see commitment" from other parties and the private sector.

Another concern was the lack of progress in governments' undertaking to review national biodiversity strategies to bring them in line with the Aichi Targets. So far only about 30 of the 194 parties have submitted an update.

Observers are hoping ministers and ambassadors gathering for a "high-level" meeting on October 15 and 16 will emerge with a strong political message on the need to save the planet.

As things stand, the situation is "pretty alarming", Brown said.

"The general policy environment of governments still mitigates against us being able to be succesful," she said, citing financial incentives like tax breaks or subsidies for resource-destroying infrastructure development projects.

On the other hand, "what Nature gives us in terms of fresh water..., providing fisheries, providing pollination..., providing clean air, filtering pollution, we generally account for that at zero when we are doing the book-keeping in our nations."

The meeting will mark the entering into force of the Nagoya Protocol, which deals with the proprietary rights of traditional communities to the genetic data of species used by foreign scientists.