Swiss Climate Verdict: Why Carbon Budgets Mattered To The Judges

(MENAFN- Swissinfo) The European Court of Human Rights (ECHR) recently ruled that Switzerland had failed to meet its own climate targets and to set a national carbon budget. What's behind this budget, and why does it matter?

Born in London, Simon is a multimedia journalist who has worked for since 2006. He speaks French, German and Spanish and focuses on science, technology and innovation issues.

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On April 9, Europe's top human rights court ruledExternal link in favour of a group of elderly Swiss women, the KlimaSeniorinnenExternal link , who said the government's inadequate efforts to combat climate change put them at risk of dying during heatwaves.

+ Landmark ruling: Switzerland's climate policy violates human rights

Summing up, the ECHR saidExternal link the Swiss government had failed to comply with its own targets for cutting emissions and had“failed to quantify, through a carbon budget or otherwise, national greenhouse gas emissions limitations”.

This is welcome news for Georg Klingler, a climate specialist with Greenpeace Switzerland, which initiated and funded the lawsuit.“Now the court says you need to stick to the laws and commitments you made, and you need to actually prove they can work,” he tells SWI swissinfo.

A carbon budget is a tool used by climate researchers and policymakers to help determine the framework and direction of climate policy. It often refers to the total amount of CO2 that can still be emitted by human activities while limiting global warming to a specified level (e.g., 1.5°C or 2°C above pre-industrial levels ). The total is then divided among countries according to“fair shares” and other criteria (see below).

A number of countries have set interim targets using carbon budgets. The UK was among the first in 2008; it has set legally binding emission caps over successive five-year periods. France, Germany, Ireland, Nigeria and New Zealand are also using carbon budgets in their planning.

But calculating a carbon budget and determining a country's“fair share” is not straightforward or easy to enforce.

To keep warming below the ambitious the 1.5°C mark agreed under the Paris climate accord, the United Nations Intergovernmental Panel on Climate Change estimatesExternal link that humans can only emit about 500 billion more tonnes of CO2 into the atmosphere starting in 2020.

Some scientists have since loweredExternal link this estimate to 250 billion tonnes. We're currently burning about 40 billion tonnes of CO2 globally per year.

The IPCC calculation of a remaining carbon budget is based on what are essentially subjective choices: the global warming level that is chosen as a limit; the probability with which we want to ensure that warming is held below that limit and how successful we are in limiting emissions of other greenhouse gases, such as methane or nitrous oxide.

And when dividing up the remaining carbon budget by country, value judgements must consider issues such as equity, fairness and differences such a population size, level of industrialisation, historic emissions and mitigation capabilities, the UN body says.

Rather than taking a top-down carbon budget allocation approach, the 2015 Paris Agreement went for a bottom-up approach based on individual country-level commitments. When setting their climate promises – known in UN jargon as“Nationally Determined Contributions” or NDCs – the Swiss are obliged to consider the principle of fairness under Article 4(3) of the climate treatyExternal link . But it is up to them to decide what that fair share is.

Switzerland has committed to halve CO2 emissions by 2030 External link and ultimately eliminate emissions by 2050External link . The Alpine nation has argued that there are no uniform, internationally-recognised guidelines for country-specific carbon budgets. It was therefore not possible to clearly determine Switzerland's share of the overall budget. And the government saysExternal link the existing 2030 and 2050 goals support scientific consensus on the overall reductions needed.

But the government has previously presented a rough figure: nearly one billion tonnes of CO2 equivalents that would be achieved through cumulative emission reductions between 2021 and 2050.

In support of the lawsuit before the ECHR, scientists have calculatedExternal link that Switzerland's remaining budget, based on population size and historic emissions, is actually much lower: 381 million tonnes of CO2 from January 2022 onwards. And to stay within this budget, Switzerland would need to reach net-zero by 2040, not 2050 as is currently planned, they say.

Switzerland's Federal Justice Office is now analysing the full Strasbourg judgement and the measures to take.

For Nikki ReischExternal link , director of the Climate and Energy Programme at the Centre for International Environmental Law (CIEL), the court's focus on a carbon budget is important, because“it makes clear that Switzerland needs to set a hard limit on its future emissions and stay within it”.

Chris Hilson, a professor of law at the University of Reading, on the other hand, calls it the“most ambiguous and potentially contentious part” of the climate ruling.

“It is clear that member states must now adopt carbon budgets. But is
how
these budgets are determined a matter for the courts?” he asks in a recent blog postExternal link published by Colombia Law School.

While in general the climate judgement had been“admirably clear”, uncertainty around carbon budgets seems likely to be pursued in national courts and may come up again at the ECHR, the law expert wrote.

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Edited by Sabrina Weiss/Veronica De Vore

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