Global warming of at least 6°C could be possible by the end of the century as decarbonisation is stagnating, according to PwC, confirming its fears that the 2°C degree target is highly unrealistic.
An annual carbon emission reduction rate of 5.1% per unit of GDP from now to 2050 is needed to limit temperatures from rising more than 2°C above pre-industrial levels, an increase from last year’s estimate of 4.8%, says PwC in its annual Low Carbon Economy Index report.
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Such a decarbonisation rate would be a massive leap compared with the 2011 rate of improvement in carbon intensity of 0.7% on average globally. Adding to the worries is the fact that 2011’s figure is lower than the 0.8% average between 2000 and 2011.
The consultancy firm's report warns that “governments and businesses can no longer assume that a 2°C warming world is the default scenario”, adding that any investments in long-term assets or infrastructure need to address far more pessimistic scenarios.
The index evaluates the rate of decarbonisation of the global economy needed to limit global warming to 2°C, and its London-based director of sustainability and climate change Jonathan Grant said earlier this month it considered scrapping the 2°C target for a 3°C or 4°C target instead.
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While maintaining the 2°C goal in the report’s calculations, Leo Johnson, partner at PwC’s sustainability and climate change team, warned that “it’s time to plan for a warmer world” as governments’ 2°C ambitions – formally agreed at the climate talks in Copenhagen in 2009 – appear highly unrealistic.
“Even doubling our current rate of decarbonisation would still lead to emissions consistent with 6°C of warming by the end of the century,” he said.
A six-fold improvement in the global decarbonisation rate is needed to have a 50% chance to meet the goal – illustrating the challenges facing negotiations at the UN climate talks in Doha in less than a month.
“We have passed a critical threshold – not once since World War Two has the world achieved that rate of decarbonisation, but the task now confronting us is to achieve it for 39 consecutive years,” Johnson said.
The report compared the required annual decarbonisation rates between now and 2050 for the G20 countries, with Spain at the lowest end of the scale with 3.6% and Saudi Arabia having to reduce its emissions the most with 7% per year for the 2°C target to be met.
“Even if it might be achievable in the longer term, it is unrealistic to expect that decarbonisation could be stepped up immediately – which means the reduction required in future years is likely to be far greater than 5.1%,” the report says.
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“Whilst negotiators continue to focus on 2°C, a growing number of scientists and other expert organisations are now projecting much more pessimistic scenarios for global temperatures,” it adds, with for example the International Energy Agency considering both 4°C and 6°C scenarios in its latest analysis.
By. Elza Holmstedt Pell
The fact is that there's absolutely no evidence to substantiate the hypothesis of an increase of more than about 1 degC. It's based on the assumption of positive feedback (eh warming from increased humidity)dominating negative feedback (eg increased cloud density). No-one dares to actually predict that it will happen (so far all predictions have failed to match real data. With no warming for the past 16 years, it's impossible to substantiate any warming prediction.)