The countries most vulnerable to global warming are calling for an ambitious, even audacious, temperature goal at the Paris climate talks.

Thoriq Ibrahim, environment and energy minister of the Maldives and chairman of AOSIS, said the group’s member countries are especially at risk to “climate extremes and climate change impacts.”

Here’s what you need to know about the 1.5-degree target:

MORE AT THESTAR.COM

Paris climate change conference: Highlights from day 9

Radical innovation is necessary to hold warming to Paris targets, experts

Wasn’t 2 degrees Celsius warming the goal, and aren’t we already locked in?

2 degrees Celsius is a working target that has been largely recognized as the limit beyond which we will seriously harm the planet. But the bar can be set higher, experts say.

Some climate experts have said that it is impossible to avoid even 2 degrees Celsius warming.

But Michael Mann, a climate scientist at Penn State University’s Earth System Science Centre, believes differently. “I don’t believe that we are committed to 2 degrees Celsius… I’ve argued that it is still doable.” But that scenario, he says, requires extremely rapid reductions in fossil fuel burning and active carbon removal — like using technology to suck carbon out of the atmosphere.

Is the 1.5 degrees Celsius target possible?

Yes, says Mann. But it won’t be easy.

The reductions would have to be even more rapid, “perhaps unrealistically rapid, approaching cold turkey on carbon emissions, and/or more carbon capture,” he says.

For Tom Pedersen, climate scientist at the School of Earth and Ocean Sciences at the University of Victoria, a 1.5 degrees Celsius goal will need intense measures internationally. “It’s not something that can be done by one country on its own. But it is not out of the realm of possibility…if every country on the planet pulls its weight.”

In tangible terms, it means that “we need 80 per cent or more reduction in emissions by 2050, an incredibly difficult challenge.”

What is the difference between 1.5 and 2 degrees Celsius?

Low-lying island nations have said that 0.5 degree could mean the difference between doom and survival.

Climate scientists have said that keeping warming to 1.5 degrees could raise the chance of survival for coral reefs, slow the rise in the number of severe weather disasters, and help keep the planet from hitting the dreaded but so far unseen tipping points of irreversible damage.

Which are the countries that have endorsed it?

The members of the Alliance of Small Island States, including small, low-lying countries in the Caribbean, Indian Ocean, Mediterranean, Pacific and South China Sea and in Africa, have endorsed it.

Canada, France, Germany, England, Australia and China also backed the target this week.

Loading... Loading... Loading... Loading... Loading... Loading...

Saudi Arabia is among the countries that have sought to block even the mention of 1.5 degrees Celsius goal in text.

Tiny island nations are leading this call. What does that say?

It says that these countries that are on the frontlines are feeling the effects already, said Pedersen.

“What we are doing in Canada, and other industrialized countries, is increasing their vulnerability to changes that are already hitting them hard. There’s a very strong, powerful moral argument behind all this.”

With files from The Associated Press

Read more about: