More than a fifth of European wild bee species, including bumblebees and cellophane bees, risk becoming extinct — as nearly 100 new species join the growing list of those under threat.

That's according to the latest International Union for Conservation of Nature Red List, which also shows that the number of threatened European butterfly species increased by approximately three-quarters over the last decade.

The list is considered the definitive global assessment of species' extinction risk, and aims to guide policymakers around the world in environmental lawmaking. It comes as the IUCN congress — a “once-every-four-years gathering of nature conservation experts, leaders and decision-makers from around the world” — unfolds in the United Arab Emirates capital, Abu Dhabi.

This year’s IUCN meeting, taking place until Oct. 15, falls as the EU comes under increasing pressure to roll back several of its green laws including its anti-deforestation regulation and the nature restoration law, both of which were only adopted in the past couple of years.

Fifteen species of bumblebees, which pollinate legume plants like peas and peanuts, are now classified as threatened. The mining bee species, described as the "only species of this genus in Europe and unique to the continent" is now "critically endangered."

Habitat loss is still the main threat to European wild bees and butterflies, but it now affects more species than ever before. That's mainly down to increasingly intense agriculture and forestry. The IUCN's global assessment released on Friday showed that more than half of all bird species are in decline, with deforestation driving sharp falls in populations across the planet.

The European-level assessment “provides the data needed to drive urgent conservation action, guide recovery efforts and support European countries in delivering on the Global Biodiversity Framework targets,” said IUCN Director General Grethel Aguilar in a statement.

The European Commission — the EU's executive arm — is currently working on a legislative bill to roll back bits of environmental law deemed too burdensome for businesses. Farming and landowner associations are lobbying hard for that bill to slash elements of the EU's anti-deforestation regulation and the nature restoration law.

The IUCN report comes months after the Commission unveiled a new proposed structure to the EU seven-year budget — which eliminates dedicated biodiversity funding.