1.5°C is better for all of us, but it means one thing: we have to keep more fossil fuels in the ground.
One target has stormed back into contention at the Paris climate talks: 1.5 degrees Celsius. That number has been around for years, but in the past it was only pushed by a coalition of small island states and most vulnerable countries. Now that coalition has fresh backing from the likes of Canada, Australia, France, the USA and China. It has a good chance of being contained in the final text that emerges from the talks. Here’s three important things you should know about the number:

1.5 to stay alive

The best thing about 1.5° C: It is better for all of us – not just small island states

The 1.5 degree target is usually talked about for the fact that it would give low-lying atolls a chance of survival than the 2 degrees target. This is true. But missing from that story is that 2 degrees of warming would be incredibly damaging irrespective of whether you live in a small island state or a large developed nation. We need to recognise that 2 degrees has never represented climate safety — it actually represents the threshold between ‘dangerous’ and ‘extremely dangerous’ climate change.

Limiting warming to 1.5 degrees would give hundreds of millions of people all over the world a greater chance of survival and prosperity. Whether it’s reducing exposure to severe drought, flooding, spread of disease, intensity of typhoons or sea level rise, scientific studies conclusively say the damage will be profoundly reduced by staying within 1.5 degrees of warming.

1.5 degrees is better for us all, and we should be thanking small island states like the Marshall Islands for their tremendous leadership in fighting to put 1.5 back into contention.

1.5° of warming still brings severe impacts

Earlier this year it was announced that the world had crept past 1 degree of human-driven warming since 1880. The cost of that warming is increasingly well documented, and it hurts.

For example, scientists at Columbia University released a study that found global warming increased the severity of California’s drought by 8 – 27% across the period 2012 – 2014. This year alone, the California drought has cost the State 2.7 billion dollars, and led to the loss of 21,000 jobs. Beyond that, it has caused tremendous hardship and personal strain for thousands of people.

At the same time, Ethiopia and much of the Horn of Africa is now gripped by its worst drought in 50 years. It is expected that 10.1 million people will face critical food shortages in the coming year, with 400,000 children at risk of developing acute malnutrition. Global warming has a distinct footprint in intensifying the drought in Ethiopia.

Every extreme weather event now happens in the context of a warmer, wetter and angrier climate.

Reaching 1.5° C is only possible if we keep fossil fuels in the ground

This point is really short but the politics that are preventing it from happening are long and ugly. To limit warming to 1.5 degrees requires one thing: to keep fossil fuels in the ground – big time.

According to the Fifth Assessment report of the IPCC, for a 50 per cent probability of limiting temperature increase to 1.5°C, the total carbon dioxide emissions allowed from 2011 till 2100 amount to a mere 550 gigatonnes (Gt) of CO2.

If all fossil fuel reserves were burnt by 2050, we’d blow out 2900 gigatonnes. On top of that, we also release significant quantities of CO2 by clearing forests and producing cement, while continued growth in other greenhouse gasses like methane make the challenge of staying within 1.5 degrees that much harder.

I’ve done some quick number crunching, and to have a 50:50 chance of staying within 1.5 degrees of warming, my estimate is 85 – 90 per cent of fossil fuel reserves need to stay in the ground (and that may be conservative). At the same time, we will need to reverse the trend of rapid deforestation, by supporting new forest sinks, and reducing emissions from agriculture. If we don’t do those things, more fossil fuels will need to stay in the ground.

Writing in The Hindu, a group of scientists outlined the very real challenge in achieving this:

“The carbon space for a 1.5°C target is so limited that developed countries will have to reach net zero emissions in next 5-10 years. Developing countries will have some more time, but their development space will be so constrained that they will need massive support in terms of finance, technologies and capacity so that they are able to meet their basic development and poverty alleviation needs while remaining within the available carbon budget.”

It will take an incredible political commitment to achieve such a rapid and radical overhaul of our global energy system. While the Paris text might include the 1.5 degree target, the measures to achieving it are woefully lacking. That’s why in the months following the Paris talks, 350.org will be scaling up our efforts to keep fossil fuels in the ground. Get ready, and join us for bold action!

One of our scientist friends Lucky Tran also interviewed some fellow scientists while here at COP about what 1.5°C means

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