Have we already blown our carbon budget?

Clear climate protection benchmarks - like a set amount of carbon we can release before unmanageable impacts set in - make a complex topic easier to grasp. But headlines don't always get the details right.

A recent study in "Nature Climate Change" made headlines with the warning that the global carbon budget - which refers to the amount of carbon we can release into the atmosphere before we exceed climate change targets - might be a lot less than we thought.

Nature and Environment | 08.05.2017

That's because projections for temperature rise tend to work from the baseline "pre-industrial" temperature of the late 19th century.

The study's authors say human activity had begun warming the planet much earlier - meaning we might have to reduce our emissions by up to 40 percent more than planned.

Yet as dramatic as that sounds, lead author Andrew Schurer says the real message of the study is that if we're going to have rigorous targets - like the 2 degrees Celsius (3.6 degrees Fahrenheit) enshrined in the Paris Agreement - these need to be properly defined.

Nature and Environment | 30.01.2017

"If we really want the targets defined relative to a pre-industrial baseline then it is likely that we may need tougher mitigation than we previously thought," he told DW.

To avoid the worst effects of climate change, most of our fossil fuel reserves will have to stay in the ground

Nice round numbers

Climate change is an immensely complex process. To grasp how urgent the situation is and plan action, huge volumes of data and analysis are boiled down to clear boundaries that we cannot cross: like a limit in increase of the average temperature of our planet by more than 2 degrees Celsius.

It's a target designed to balance what we can bear in terms of climate impacts with what we can realistically aim to achieve in terms of emissions cuts.

The concept of the carbon budget indicates how much carbon we can release into the atmosphere before global warming reaches that 2-degree rise in global temperatures. This has been estimated at around 3,000 gigatons - of which we have already squandered about two-thirds.

Clear messages for decisive action

Luke Sussams of Carbon Tracker Initiative says his organization seized on the carbon budget as a useful - and increasingly popular - tool to communicate the scale and urgency of the problem.

"It is the most simple way, and therefore the most effective way, to frame the problem," Sussams told DW.

The main appeal of the carbon budget is that it allows experts to calculate how much of the world's fossil fuel resources we have left. Carbon Tracker estimates that anywhere between two-thirds and four-fifths of remaining coal, oil and gas reserves are "unburnable."

Given that a hefty share of those reserves is already factored into the balance sheets of fossil fuel companies, the need for urgent action becomes starkly clear.

And that's helped spur concrete action - like the movement to divest from companies counting on profits that can only be realized if the global aim of keeping emissions in check is tossed aside.

But the carbon budget has its limitations.

Politically impossible

"Politically, [carbon budget] is perhaps not that useful," Sussams admits. "Because if you are going to actually use the carbon budget to then go across the 196 countries and hold them to 2 degrees - how would you divide it up?"

The Global Carbon Project has had a go. Its Global Carbon Atlas visualizes different ways to dole out fossil fuel resources, taking into account factors like population size and inertia (the idea that you cannot realistically expect carbon-heavy economies to suddenly go cold turkey).

Josep Canadell of the Global Carbon Project said even their estimates present problems. "Now matter how you cut the pie, you have the developed world - Germany, and anyone else in Europe, the United States, Australia and Japan - eating more than their share," he told DW.

These political complications are why the United Nations climate framework has long since abandoned carbon budget as any basis for negotiations over national contributions to climate action.

Some believe 100 percent renewable energy is not a realistic goal for a short time frame

"You can just imagine the sort of pushback, and the uproar, if a country thought they weren't given enough of a carbon budget," Sussams said. 

Carbon overdraft

In fact, Canadell said, the UNFCCC's crowning achievement inherently accepts the impossibility of keeping within the carbon budget.

"The reality is that by signing the Paris Agreement, we actually have signed into allowing the carbon budget to be overblown," Canadell said. "We have signed to go beyond the carbon budget in the first part of the century - and in the second part of the century, we do negative emissions."

"Negative emissions" means that not only do we - the humans who will still be around after 2050 - have to stop emitting carbon; we will have to actually start removing it. 

This would rely on large-scale and affordable carbon capture and storage (CCS) - which has so far been elusive. Nuclear energy is also often cited as a bridging solution - although this certainly carries it own risks

In any case, Canadell believes delaying action is a slippery slope. 

How soon is now

"The risk is that is if we are going to overblow the budget, you can always say: Well, let's blow it away a little more so we can relax a bit. We'll fix it later - of course by a different generation than our own," he says.

Yet simplifying things into an easily-grasped concept - the carbon budget - brings its own uncertainties.

Carbon dioxide is the biggest climate change culprit. But the carbon budget makes assumptions on a myriad of other factors - such as how quickly we will be able to remove aerosols from the atmosphere and reduce emissions of other greenhouse gases like methane - that are little better than guesswork.

In reference to Schurer's study on changing the baseline for "pre-industrial," Canadell said: "We had plenty of uncertainty - now we have more."

"But the main message doesn't change," he added.

Which is: Fending off climate catastrophe will be an uphill battle, wherever you set the limit. 

How to stop climate change? Start now!

Number 10: Upgrade lightbulbs

You just bought a fancy lamp? Make it cooler with efficient lightbulbs. This is one of the small actions that make a difference in the long-term - and let's be honest, it's not a big effort. Some LED bulbs consume up to 90 percent less than traditional ones.

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Number 9: Hang laundry to dry

In cold or rainy countries, the task might be challenging - but these challenges are nothing compared to the worst consequences of climate change.

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Number 8: Recycling

Recycling has become normal behavior for thousands of people around the world. It definitely contributes to making a better world - but unfortunately, it is not enough.

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Number 7: Wash clothes on cold

Worried about your clothes shrinking in hot water? Here another reason to keep washing with cold water: Since it avoids turning on the water heater, cold-water washing also produces less greenhouse gas emissions.

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Number 6: Drive a hybrid

Until you are ready to get rid of your car completely, you could move to a hybrid electric car. But beware: The electricity that powers it is probably still coming from dirty fossil fuels.

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Number 5: Switch to a vegetarian diet

Beef production is the largest driver of tropical deforestation worldwide, with soy production closely following - mainly to feed animals. The carbon footprint of a meat-based diet is almost double that of a vegetarian one. Even reducing the amount of meat you eat makes a difference.

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Number 4: Buy green energy

Renewable energies are the new trend - but we are still largely dependent on fossil fuels such as coal. In countries like Germany, you can choose your energy provider - among some that draw from renewable sources.

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Number 3: Cancel one trans-Atlantic flight

Air travel is a major challenge when it comes to tackling climate change. Policy-makers are exploring ways to reduce the climate impact of flights - but in the meantime, you can start thinking twice before taking a plane. Particularly to cross the pond.

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Number 2: Don't use a car

Getting rid of your car is the second-most effective action you can take to tackle climate change. And riding your bike also helps keep you fit!

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Number 1: Have one less child

Giving birth to a new person consuming and polluting at the current rate of people in industrialized countries is the worst thing you can do for the planet, according to the study. But if you start now with the other nine actions, your kids might be able to live in a better world.