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Department of Mechanical, Aerospace and Civil Engineering

Reframing climate change: from long-term targets to stringent carbon budgets

Building on the results of research conducted by Tyndall Manchester, the UK government reset the carbon emissions reduction target by introducing the 2008 Climate Change Act.

Case study

80% emissions reductions icon


The minimum reduction in carbon emissions required by 2050 to help keep global warming below 2°C.

Global temperatures are warming: sea levels are rising, crops are failing and freak storms are increasing in intensity. Governments worldwide are beginning to heed the warnings of scientists and take preventative action to prevent catastrophic, irreversible climate change. In 2009 the UK government signed the Copenhagen Accord, which commits the country to playing its fair role in limiting temperature increases to no more than 2°C above pre-industrial levels.

But controlling temperatures means slashing emissions. In a bold step, the UK demonstrated its commitment to the climate change agenda by drafting the Climate Change Bill, which went through Parliament in 2008.

Both the budgets and the 80% reduction have proved to be highly influential; they were presented as evidence to climate change policy makers, including at select committee hearings, HM Treasury and to the government's chief scientist.

The Bill initially proposed that carbon emissions should be cut by 60% by 2050. But Tyndall Manchester's research showed that this reduction was not enough to keep the global temperature rise within the 2°C zone. The research showed that only radical emission cuts of at least 80% might stop global temperatures from rising higher.

This figure is now enshrined in the Climate Change Act, which became law in November 2008 and makes the 2050 emissions reduction target of 80% a legal obligation for the government. David Miliband, the Labour government's Environment Secretary from 2006-07, acknowledged the "signal contribution" of the Tyndall Manchester research to setting of the target.

Other outcomes

The research also informed the work of the Welsh Assembly and the Scottish Parliament, which passed the Scottish Climate Change Act in 2009 with the same 80% target.

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The proposed 2050 emissions reduction target, shown by Manchester research to be insufficient.

The Tyndall Manchester team also advised the UK government to accompany its long-term emissions targets with short-term goals - called 'carbon budgets' - to account for cumulative emissions. They also presented evidence that targets and carbon budgets should include international aviation and shipping emissions. These recommendations were also incorporated into the Climate Change Act with carbon budgets now established for the period 2008 to 2027. The budgets cover domestic aviation and shipping, although the government deferred a decision to include international emissions from these activities due to the uncertainty on an international framework for reducing these emissions.

Research background

Tyndall Manchester research project 'Decarbonising the UK' developed energy scenarios in which it was possible to meet the UK government's target for reducing carbon emissions. Scenarios were created by integrating the perspectives of engineers and economists along with environmental and social scientists. This unique method was later used to develop potential emission scenarios for China.

Carbon budget icon

Carbon budget

The proposed limits on CO2 emissions that would keep global temperatures within a defined range.

The researchers explored the role of international shipping and air transport in targets because the Kyoto Protocol does not account for these international emissions - a loophole that has undermined the success of national reduction targets in fighting climate change.

This initial research underpinned a wealth of interdisciplinary, whole-system analyses of energy and emissions at UK and global levels. Further research focused on the transition from long-term reductions targets to scientifically robust cumulative emissions and carbon budgets. The research was the first ever analysis to focus on the necessary measures to prevent global warming exceeding the 2°C threshold between acceptable and dangerous climate change.