Experts say CO2 emissions could make it too warm for species living in marine protected areas (MPAs).

Researchers analysed future warming trends for over 8,000 MPAs around the world and compared them to the natural temperature ranges of local species.

They found a number of areas in the tropics will become too warm for their inhabitants by 2050.

In just over three decades’ time, the study found 42 per cent of areas with fishing bans will be exposed to warming waters and decreasing oxygen levels that exceed natural variability.

Researchers investigated 8,263 MPAs, including 309 areas where fishing is banned.

They modelled sea surface temperatures and oxygen concentrations at both moderate and high emissions scenarios to predict the impact on protected ecosystems.

From this, they calculated a ‘community thermal safety margin’ (CTSM) for each ecosystem, which is — for all species present — the average of the margin between each species’ temperature tolerance and the local maximum temperature.

Exceeding the CTSM could lead to substantial loss of biodiversity.

The authors show that marine protected areas are predicted to warm at a similar rate as unprotected areas, with the exception of the polar regions.

The tropics will be the first to exceed the CTSM by about 2050, with temperate latitudes following by around 2150.

The study is accessible here.