By Olivia Oldham
What does 'common but differentiated responsibility' (CBDR) mean?
Common but differentiated responsibility (sometimes with the addition of the phrase 'and respective capacities') is a principle of international law which means that different countries have different capabilities and responsibilities to address cross-border environmental issues such as climate change. It balances:
How does CBDR work?
Under the Paris Agreement, all signatory countries are obliged to mitigate their carbon emissions through the 'Nationally Determined Contribution' (NDC) mechanism 3, 4.2). Because countries can voluntarily set their own NDC's, their respective obligations can be substantially differentiated.
Differentiation between different countries' obligations is also provided for in other ways throughout the agreement, including:
What's the history of the concept?
The Montreal Protocol (1989)
An early example of the CBDR principle can be found in the Montreal Protocol, a reasonably successful treaty that dealt with the emission of chemicals causing the destruction of the ozone layer. This involved:
UN Framework Convention on Climate Change & Rio Declaration (1992)
The Kyoto Protocol (1997)
Why is CBDR controversial?
Some countries have gained new capabilities, and their emissions have dramatically increased since 1992 (e.g. China, India, the UAE, Singapore). These countries' contributions to global Green House Gas (GHG) emissions, as well as their capacity to address the problem are likely to continue to grow. Given the urgency of the climate emergency, it can be argued that these countries need to shoulder greater responsibility in order for the Paris Agreement targets to be met.
The above argument partly reflects a wider disagreement about the role of historic versus current responsibility for the problem and the role of equity (as opposed to a simpler approach of equality) in addressing climate change. For example, the USA rejected "any interpretation of [CBDR] that would imply a recognition or acceptance by the United States of any international obligations or liabilities, or any diminution in the responsibilities of developing countries" all the way back in 1992. This is one of the reasons why the USA was not a party to the Kyoto Protocol, and why the PA now contains a weaker version of the principle.
Why does it make sense, despite the controversy?
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