Shun meat, says UN climate chief

Livestock production has a bigger climate impact than transport, the UN believes

People should consider eating less meat as a way of combating global warming, says the UN’s top climate scientist.

Rajendra Pachauri, who chairs the Intergovernmental Panel on Climate Change (IPCC), will make the call at a speech in London on Monday evening.

UN figures suggest that meat production puts more greenhouse gases into the atmosphere than transport.

But a spokeswoman for the UK’s National Farmers’ Union (NFU) said methane emissions from farms were declining.

People may not realise that changing what’s on their plate could have an even bigger effect Joyce D’Silva Compassion in World Farming

Dr Pachauri has just been re-appointed for a second six-year term as chairman of the Nobel Prize-winning IPCC, the body that collates and evaluates climate data for the world’s governments.

“The UN Food and Agriculture Organization (FAO) has estimated that direct emissions from meat production account for about 18% of the world’s total greenhouse gas emissions,” he told BBC News.

“So I want to highlight the fact that among options for mitigating climate change, changing diets is something one should consider.”

Climate of persuasion

The FAO figure of 18% includes greenhouse gases released in every part of the meat production cycle – clearing forested land, making and transporting fertiliser, burning fossil fuels in farm vehicles, and the front and rear end emissions of cattle and sheep.

Dr Pachauri has chaired the Nobel Prize-winning body since 2002

The contributions of the three main greenhouse gases – carbon dioxide, methane and nitrous oxide – are roughly equivalent, the FAO calculates.

Transport, by contrast, accounts for just 13% of humankind’s greenhouse gas footprint, according to the IPCC.

Dr Pachauri will be speaking at a meeting organised by Compassion in World Farming (CIWF), whose main reason for suggesting people lower their consumption of meat is to reduce the number of animals in factory farms.

CIWF’s ambassador Joyce D’Silva said that thinking about climate change could spur people to change their habits.

“The climate change angle could be quite persuasive,” she said.

“Surveys show people are anxious about their personal carbon footprints and cutting back on car journeys and so on; but they may not realise that changing what’s on their plate could have an even bigger effect.”

Side benefits

There are various possibilities for reducing the greenhouse gas emissions associated with farming animals.

They range from scientific approaches, such as genetically engineering strains of cattle that produce less methane flatus, to reducing the amount of transport involved through eating locally reared animals.

“The NFU is committed to ensuring farming is part of the solution to climate change, rather than being part of the problem,” an NFU spokeswoman told BBC News.

Unnatural roots of the food crisis Snared in a homemade ‘NitroNet’

“We strongly support research aimed at reducing methane emissions from livestock farming by, for example, changing diets and using anaerobic digestion.”

Methane emissions from UK farms have fallen by 13% since 1990.

But the biggest source globally of carbon dioxide from meat production is land clearance, particularly of tropical forest, which is set to continue as long as demand for meat rises.

Ms D’Silva believes that governments negotiating a successor to the Kyoto Protocol ought to take these factors into account.

“I would like governments to set targets for reduction in meat production and consumption,” she said.

“That’s something that should probably happen at a global level as part of a negotiated climate change treaty, and it would be done fairly, so that people with little meat at the moment such as in sub-Saharan Africa would be able to eat more, and we in the west would eat less.”

Dr Pachauri, however, sees it more as an issue of personal choice.

“I’m not in favour of mandating things like this, but if there were a (global) price on carbon perhaps the price of meat would go up and people would eat less,” he said.

“But if we’re honest, less meat is also good for the health, and would also at the same time reduce emissions of greenhouse gases.”

Sea level rise by 2100 ‘below 2m’

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A revamp of the Thames Barrier is likely as sea levels rise

Sea levels globally are very unlikely to rise by more than 2m (7ft) this century, scientists conclude.

Major increases would have to be fuelled by a faster flow of glaciers on the Greenland or Antarctic ice sheets.

But writing in the journal Science, a US team concludes that a rise of 2m would need glaciers to reach speeds that are “physically untenable”.

However, even increases substantially less than 2m would cause major issues for many societies, they say.

“Even a sea level rise of 20cm (8in) in a century will have quite dramatic implications,” said Shad O’Neel from the US Geological Survey (USGS).

Woe betide any government that thinks a 2m rise in sea level isn’t something to take notice of Dr David Vaughan British Antarctic Survey

“This work is in no way meant to undermine the seriousness of climate change, and sea level rise is something we’re going to have to deal with,” he told.

Al Gore’s documentary An Inconvenient Truth received some criticism for implying that a rise of 20ft (6m) was possible in the near future, although it did not give a definite timeframe.

By contrast, this latest research tallies broadly with the conclusions of other groups that have examined the question using different approaches.

Fast work

In its landmark assessment of climate change published last year, the Intergovernmental Panel on Climate Change (IPCC) concluded that sea level rise would probably fit in the range between 28 and 43cm over the century, although 59cm was a possibility.

The current rate is about 3mm per year.

But the IPCC specifically excluded the mechanism able to produce the biggest amounts of water quickly – acceleration in the flow of ice from the Greenland and Antarctic ice sheets, the world’s two major ice masses that would between them raise sea levels by about 70m if they completely melted.

Most of the ice comes off in glaciers. Scientists know that many of the glaciers have accelerated in recent years – some quite spectacularly. The Jakobshavn glacier in Greenland, for example, doubled its speed in six years to about 12km per year.

The acceleration of glaciers is not well understood

But the processes involved are poorly understood, and the IPCC concluded that on that basis it would be unreasonable to draw any conclusions about how far the acceleration might go.

Individual scientists, however, have not be so coy. The team behind the current research looked at what we do know about Greenlandic and Antarctic glaciers, about the rates of flow and the factors that might prevent acceleration.

“We don’t really know a speed limit for glaciers,” said Dr O’Neel, “but we can look at what we have today and ask ‘what would happen if they all behaved like Jakobshavn?’

“It’s been going fast for several years now and hasn’t gone another marked increase in speed. Helheim had a brief period at 14km per year, Columbia at nine or 10; so that kind of figure, in the region of 10km/year, seems to be about as fast as it gets.”

To achieve a 2m sea level rise by 2100, by contrast, every Greenland glacier would have to increase its flow rate to at least 27km per year and remain at that velocity for the rest of the century.

‘Scary’ scenario

Antarctica is rather different. The West Antarctic Ice Sheet rests on rock that is mainly below sea level, meaning that warming seas could increase the rate of ice loss, though again the new analysis suggests this is also very unlikely to result in a catastrophic melt during this century.

David Vaughan from the British Antarctic Survey believes the US team has got its figures about right.

“The point is that whatever happens in this century can only start from present conditions and present rates of sea level rise, and that constrains the rise that can occur this century,” he told.

“However, if you’re looking further ahead than 2100 – and many governments are, including the Netherlands and the UK which are thinking about infrastructure that would last more than 100 years – then that second century still looks quite scary.

“I certainly don’t disagree with them that we shouldn’t be making outlandish statements about sea level rise, and some outlandish statements have been made; but the high end of the estimates here is still about 2m, and woe betide any government that thinks a 2m rise in sea level isn’t something to take notice of.”