Science & Environment

Carbon emissions divide 'can be bridged'

Chinese solar manufacturing plant
Image caption Manufacture and use of technologies such as solar is forging ahead in China

The gap between where greenhouse gas emissions are headed and where they need to be for climate targets can be bridged cheaply, says a UN report.

It says that if sectors such as energy, farming, forestry and transport all cut emissions by feasible amounts, global warming can be kept below 2C.

But countries' current pledges are not enough to meet the 2C target.

The report, Bridging the Emissions Gap, comes shortly before this year's UN climate summit opens in South Africa.

The United Nations Environment Programme (Unep) combined analyses from 28 research centres around the world, looking both at projections of future emissions growth and at what can be achieved in different sectors.

Nothing revolutionary is needed, they conclude, if every sector makes its appropriate cuts. And the cost would be small.

"At the beginning, the reductions are cost-neutral - or you can gain because they include things like energy efficiency that save fuel costs," said Joseph Alcamo, Unep's chief scientist.

"We didn't find that any technological breakthroughs were needed to close the gap."

Divided world

Currently, global emissions of greenhouse gases each year are equivalent to about 48 billion tonnes of carbon dioxide (48GtCO2e).

If nothing changes, that will probably rise to about 56 gigatonnes (Gt) per year by 2020.

Analysis from climate models, meanwhile, suggests that emissions ought to be down to about 44Gt per year in order to have a reasonable chance of meeting the goal of keeping the global average temperature rise since pre-industrial times below 2C.

That goal has widespread support across the international community, although more than half the world's governments prefer the tougher target of 1.5C.

So if nothing changes, the 2020 target will be missed; in the jargon, there is an "emissions gap" of 12Gt.

After the UN climate summit in Copenhagen two years ago, most of the world's governments put forward pledges on either cutting emissions (for the rich) or constraining their rise (for the poor).

But even if those pledges are enacted in full, that will only halve the gap, not close it completely.

"This study, again, reminds us that efforts to address climate change are currently still insufficient," commented Christiana Figueres, executive secretary of the UN climate convention (UNFCCC).

Unep's analysis concludes that across eight sectors - power, industry, land-based transport, aviation and shipping, buildings, waste, forestry and agriculture - an emissions cut of 17Gt is feasible and cheap.

Projections show it would be possible to meet the 2C target without making such strong cuts now, though the much steeper emission cuts needed after 2020 would increase the cost.

In fact, some cheap options that were on the table four years ago are now off it, said Niklas Hohne, director of energy and climate policy at the Netherlands-based consultancy Ecofys and a lead author on the report.

"All studies agreed that there is huge potential to reduce emissions associated with buildings, for example, mainly through renovating and making them more efficient with energy," he said.

"But that takes time; and now, four years later, we have significantly less time until 2020 to implement these measures."

Delays and illusions

Many developing country governments have expressed alarm that the UN climate convention appears to be morphing from a process in which emission cuts are negotiated on the basis of the science into one where industrialised countries say unilaterally what they are prepared to do.

The latest steers from observers close to the talks suggest the situation is unlikely to change before 2020.

Achim Steiner, Unep's executive director, said that in the short term the voluntary approach was yielding some emission curbs; but in the long run, a binding climate treaty would be needed.

"There should be no illusion at all that voluntary actions will add up to anything like the transformation needed," he said.

"Those countries talking about deferring to 2020 are saying to the world 'we're taking you from a high-risk strategy to a very high-risk strategy in terms of tackling global warming'."

Waiting still further to begin curbing global emissions would see a situation where "we may already be married to a 3C rise", he said.

The UN climate summit opens in Durban, South Africa, on Monday.

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