This week, what are the chances of limiting global temperature rises to one and a half degrees?

Before Paris, there's basically no research on 1.5 degrees.

And when climate change messes with your research...

The birds migrated back at least two weeks earlier.

They were already nesting. In fact, some nests had already begun and failed by the time we were out there doing the fieldwork.

Plus, persuading people of the dangers of climate change when the weather is actually quite nice.

This is the nature podcast for April the 21st, 2016. I'm Kerry Smith.

And I'm Adam Levy.

It's a climate change special this week because this Friday the 22nd of April is Earth Day.

And to tie in, on that day, over 100 countries will sign the Paris Climate Agreement.

At the heart of the agreement, reached in December last year, is the aim

to keep global temperature increases, in their words, well below 2 degrees C above pre-industrial

levels and to pursue efforts to limit the increase to 1.5 degrees C. Adam Levy finds out what we know

about how low we can go. 1.5 degrees. It's a little number, but it was a big surprise for climate researchers when it was announced in December.

Before the Paris deal, most research on a temperature limit had focused on 2 degrees, the goal agreed in Cancun in 2010.

Before Paris, there's basically no research on 1.5 degrees.

This is Glenn Peters, who researches climate science and policy.

But basically no research doesn't mean no research at all.

Yerri Rogel has been one of the few researchers obsessing over 1.5 degrees over the last five years.

If you're looking for literature on 1.5 degrees...

Yuri's the literature.

My research has been focusing on emission scenarios to limit warming to below 1.5 degrees.

...