What are we aiming for?

Today a study was published in Nature which hopefully will ring the alarm bells loud enough for people to understand what we are up against: Climate change is an extremely serious threat, and we will lose if we do not act now.

Malte Meinhausen and colleagues have demonstrated for the first time how much CO2 can still be emitted until 2050 if we want to avoid global warming by more than 2°C.

Their result: the world can emit about 1000 billion (= 1 trillion) tons of CO2 by 2050 if we want to have a 75% chance to stay below 2°C warming. Between 2000 and 2009 the world has already emitted one-third of that amount.

The most worrying aspects of this study are:

1. As Meinhausen points out:” At present rates of emissions, we will use up the remaining two thirds in another 20 years, by around 2030. We will consume this 2000 to 2050 budget even earlier if emissions continue to increase according to the “business-as-usual” scenarios.” Unfortunately, current CO2 emissions increase faster than the most pessimistic scenario of the IPCC.
2. To ensure that we do not pass a 2°C warming, we must not burn more than one-quarter of all currently available fossil fuels (this does NOT include unconventional fossil fuels such as tar sands). It will be a major challenge to ensure that those countries and interest groups that have an interest in fossil fuels will not get to sell their riches. Therefore, the world needs to unify strongly for a strict and high carbon price that will make it uneconomical to sell or buy fossil fuels.
3. Even the emission of “just” 1000 billion tons of CO2 puts us at the incredibly high risk of 25% of passing a 2°C warming – an unacceptably high chance of failure.

So what do we need to aim for?

• We are already within a danger zone that could leave our children on a planet that might not resemble what we enjoy today.
• Therefore, we need to urgently, quickly and effectively employ all means for a sustainable low-carbon future.
• To have a reasonable likelihood of not passing a 2°C warming, we need to aim for an atmospheric CO2 concentration lower than 350 ppm.

Clearly, adequate action is still missing. What to do? The good thing is that even now we still stand a chance of making it. So, start your own campaign in your school, village, town, and city today to get ready for radical emission reductions without waiting for others to do so.

Maiken Winter

Source: Nature Press Release, PIK

Also, see the article on RealClimate, and for German readers die KlimaLounge

A great commentary on this issue is also on Climate Progress