Global warming could halve number of species in most diverse ecosystems, report states

Photo credit: CIFOR/Icaro Cooke Vieira
6 April 2018

BONN, Germany (Landscape News) — What is the price of failing to cut our carbon emissions? A catastrophic loss of plant and animal species is one cost the world would have to weather, a landmark study from the University of East Anglia, the James Cook University and the World Wildlife Fund (WWF) has found.

The study explored the impact of climate change on almost 80,000 plant and animal species in 35 of the most diverse and wildlife-rich areas of the world, such as the Amazon and the Galapagos Islands.

The report predicts species loss under three different scenarios. In a “business-as-usual” situation, where no emission cuts are made from current levels and global mean temperatures rise by around 4.5 degrees Celsius, around half of all species would likely be lost from these areas.

Some of the localized findings are even more alarming. For example, almost 70 percent of plant species in the Amazon could become extinct, as well as 60 percent of mammals and birds.

If countries uphold their current collective nationally-determined emissions-reduction commitments, the projected increase in mean temperature would be around 3.2 degrees Celsius, which would still result in significant species extinction, the researchers found.

If the U.N. 2015 Paris Agreement targets to keep global greenhouse gas emissions in check are actually met and the mean temperature increase is kept under 2 degrees Celsius, species loss in these areas would still occur, although limited to around 25 percent. But this last scenario, although most desirable, is currently highly unlikely, the paper states.

SEEING THE FOREST AND THE TREES

What do the odds look like for individual species? Those that are highly mobile, produce lots of offspring in a short period of time, and can disperse their descendants widely and quickly will be most likely to adapt and survive, the report states.

For example, plant species that produce seeds in big numbers which are spread by wind over large distances will probably find new niches, while those who drop their seeds on the ground around them “won’t be able to get themselves out of danger zones quickly enough,” according to Christopher Martius, principal scientist and head of the climate change program at the Center for International Forestry Research (CIFOR).

What’s “truly scary” about these findings is not so much the specific extinctions that are forecast, but the ecosystem malfunctioning that this level of change would imply — because the interactions between plant and animal species is what provides this functioning, Martius said.  With species at around half their former numbers: “You can imagine that many of those functions will be lost,” he said.

“If a forest or desert is not functioning in the way it should be, then you lose a lot of services like water provision, soil erosion prevention, protection against sandstorms and so on,” Martius said. “It’s bad in itself that we’re losing the species, but if we lose the functions, that’s actually when the planet starts going wild.”

CUTTING THE CARBON

The message of the report message is clear: to save species and ecosystems, we need to cut carbon emissions and limit global temperature rise as much as possible. So why is this not happening already?

One reason is the lack of ambitious, binding commitments within the Paris Agreement so far,  Martius said. While the agreement is strong on cutting emissions from the land sector, it has not yet provided countries with similar guidance for fossil fuels and other high-emission sectors.

“So far, even strongly committed countries and the EU (European Union) are on the pathway to not achieving their goals if they don’t undertake massive steps in that area,” he said. “And we’re still prospecting for fossil fuels all over the world – no-one is saying let’s leave it in the ground.”

“It’s a sad reality, but I think the common mind-set on this planet is somewhat self-contradictory,”  he said. “People on the one hand know and see what’s going on, and on the other hand they operate and act as if nothing was going on. And I can certainly include myself there: in my day-to-day work, I don’t always measure every step by its carbon footprint.”

BEACONS OF HOPE

However, Martius remains resolute that change is possible. “I think if I wasn’t hopeful, then I would probably give up my work and just go and live on the beach until it all came down!” he laughed. “I think we have a common framework to work with under the Paris Agreement, and it just needs to be taken up more seriously, and with stronger actions.”

“We have some countries currently not really interested in moving this agenda forward, and we need to rely more on the coalitions of the willing that are seeing this as a problem and that want to act on it,” he said.

“And we need to get active ourselves: to put pressure on our political representatives, and take action locally too. There are many ways to do this, and with all our efforts combined we can still achieve the impossible.”

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