Tackling global warming could slow global growth - by 0.06 per cent, IPCC predicts

  • 16 Apr 2014, 14:00
  • Mat Hope

Economists and policymakers have spent decades debating how much the world will have to pay to avoid the worst impacts of climate change, and whether it's worth the cost. A key finding in the UN's latest big climate report should help move that debate along: tackling climate change could slow economic growth by just 0.06 per cent a year, it says.

The Intergovernmental Panel on Climate Change (IPCC) released the third instalment of its review of latest climate change research last Sunday. While the first two instalments aimed to better define the climate change problem, the third report focuses on potential solutions - from ramping up wind and solar power, to halting deforestation.

But governments don't just want to know what they must do to avoid the worst impacts of climate change, they also want to know how much it will cost. So the IPCC's latest report spells out the choice: governments either pay a bit to curb emissions now, or risk much larger costs in the future.

Or, as IPCC co-chair Ottmar Edenhofer put it during the report's launch, "Climate policy isn't a free lunch but could be lunch [that's] worthwhile to buy".

Taking action is relatively cheap

In 1992, countries agreed they would curb emissions to prevent temperatures rising by more than two degrees above pre-industrial levels. 22 years on, after more than two decades of increasing emissions, that goal looks ever more ambitious.

So it may come as a surprise to find that the IPCC says the cost of keeping the pledge may be relatively low.

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From RCP to WG3: A climate change acronym cheat sheet

  • 15 Apr 2014, 11:15
  • Mat Hope

Know your AFOLU from your LULUCF? The Intergovernmental Panel on Climate Change has made great efforts to  cut the "weirdo words" and put its big climate reports into terms everyone can understand. But that hasn't stopped it from occasionally befuddling readers with a range of complex acronyms.

We decode some of the most common.


IPCC - Intergovernmental Panel on Climate Change
The IPCC is an international group of scientists set up in 1988 under the auspices of the United Nations. It doesn't do any of its own research, but aims "to provide the world with a clear scientific view on the current state of knowledge" about climate change through a series of reports released every six or seven years.

UNFCCC - United Nations Framework Convention on Climate Change
In 1992, hundreds of heads of state signed up to the UNFCCC. Under the convention, countries aim to "stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic [human-induced] interference with the climate system."


AR1/2/3/4/5 - Assessment Reports 1, 2, 3, 4 and 5
The IPCC has so far produced five reports reviewing the latest climate change research. The most recent - AR5 - is due to be released in its entirety before the end of April 2014.

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The what, when and where of global greenhouse gas emissions: A visual summary of the IPCC’s climate mitigation report

  • 13 Apr 2014, 10:50
  • Mat Hope

Erhard Renz

The UN Intergovernmental Panel on Climate Change (IPCC) released the third and final instalment of its big report today. It calls for policymakers across the globe to come together to formulate ways to cut greenhouse gas emissions and avert the worst impacts of climate change.

The IPCC provides a number of charts and graphics to illustrate the complex report - some more obvious than others. We do our best to translate three of the most startling, showing what the IPCC says must be done, when emissions need to be cut, and where those reductions can be made.

What must be done

In 1992, countries agreed to curb global greenhouse gas emissions to try and prevent temperatures from rising by more than two degrees above pre-industrial levels. For this to remain possible, countries are going to have to make some significant emissions cuts over the coming decades, the IPCC says.

This graph shows how emissions will have to change between now and 2100 if the world is going to avoid the worst impacts of climate change, according to the IPCC's modelling:

WG3 SPM Emissions Pathways

Each of the coloured strips is a different emissions pathway - or scenario - that the IPCC has modelled.

The amount of warming the world will experience is related to the proportion of greenhouse gases in the atmosphere, known as the emissions concentration. There's about a 66 per cent chance of keeping warming to two degrees if the emissions concentration stays between 430 and 480 parts per million (ppm) of carbon dioxide equivalent by 2100, the IPCC estimates - the light blue strip on the graph above.

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How to read the Intergovernmental Panel on Climate Change’s reports

  • 13 Apr 2014, 10:02
  • Mat Hope


The UN's three new climate reports are thousands of pages long and contain a huge amount of detail on topics as diverse as flood risk to bioenergy. So how do you stop them from becoming the world's best-researched doorstop? Here's our guide to navigating the reports.

Three reports

Three publications make up the Intergovernmental Panel on Climate Change's (IPCC) comprehensive review of climate change research, known as the Fifth Assessment Report (or AR5). As they're such big pieces of work, the IPCC only produces a new assessment report every five or six years.

So where do you start? First, make sure you're reading the right document.

Screen Shot 2014-04-13 At 10.16.38

Responsibility for writing the reports is shared across three sets of scientists, known as Working Groups (sometimes referred to as WGs).

The WG1 report was released last September, WG2 came out yesterday, and WG3 is due in a week's time.

The Working Group 1 report looks at the physical scientific aspects of the climate system and climate change. Working Group 2 is tasked with assessing the impacts of climate change, and options for adapting to it. Working Group 3 tries to work out how policymakers can reduce global greenhouse gas emissions, and curb climate change.

In addition to each of the working group's reports is a synthesis report which brings together all of the IPCC's research.

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A big report on how to tackle climate change will be published this weekend: How is it being reported?

  • 11 Apr 2014, 14:40
  • Mat Hope

Hundreds of scientists and policymakers are meeting in Berlin this week to discuss a major new UN climate change report. The Intergovernmental Panel on Climate Change will release the third and final instalment of its review of the current state of climate change research on Sunday.

While the first two reports aimed to better define the climate change problem, Sunday's report focuses on potential solutions. The first part of the report, released last September, covered the physical science of climate - from extreme rainfall to Arctic ice melt. The second part of the report - released at the end of March - looked at how rising emissions could affect extreme weather, food production, and human security.

Sunday's report will focus on what governments need to do to avoid the worst of those impacts. It is expected to emphasise the need for international cooperation to curb emissions, suggesting a variety of ways countries can decarbonise their economies.

With the notoriously leaky IPCC process in full swing, newspapers have been previewing some of the key findings. So what can we expect from next week's report?

Two degrees

In 1992, countries agreed to curb greenhouse gas emissions, to prevent global temperatures rising by more than two degrees above pre-industrial levels. Since then, emissions have continued to rise. The IPCC's report is expected to say that the longer this goes on, the harder it will be for countries to keep to the pledge.


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Analysis: How UK newspapers covered the IPCC’s report on the impacts of climate change

  • 03 Apr 2014, 16:15
  • Mat Hope

Emett Bergin

From food shortages to endangered species, there were plenty of headline-grabbing findings in the UN's latest big climate report. We take a look at how the UK's newspapers covered the Intergovernmental Panel on Climate Change's (IPCC) latest report.

The IPCC's Working Group 2 (WG2) report on the impacts of climate change was released on March 31st. Monday's report was the second in a series of three from the IPCC. The first report - Working Group 1's on climate change's physical science basis - was a  big story when it was released last September, so it's perhaps unsurprising that WG2's report also received quite a lot of attention.

But despite being overseen by the same organisation, the two reports are very different beasts. While journalists generally focused the WG1 report's topline finding that scientists were more certain than ever about humans influence on the climate, WG2's broad focus led newspapers to print stories on a wide variety of issues: from flooding in the UK, to famine in parts of Africa.


We searched the UK's main national newspapers for coverage of the report in the two weeks leading up to its release (a more detailed methodological note can be found at the end of the blog). There were 49 articles in the mainstream press over the 15 days our search covered.

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‘Climate change poses risks for human and natural systems’: Key quotes from the IPCC’s Working Group 2 report

  • 01 Apr 2014, 11:55
  • Roz Pidcock & Mat Hope

The Intergovernmental Panel on Climate Change released a big report on the impacts of climate change yesterday. The report looked at everything from how climate change puts species and societies at risk, to what rising emissions may mean for marine life and extreme weather events.

We pick out some key quotes from the IPCC's Working Group 2 Summary for Policymakers.

Impacts of climate change

"Human interference with the climate system is occurring, and climate change poses risks for human and natural systems"

"In recent decades, changes in climate have caused impacts on natural and human systems on all continents and across the oceans."

"Some risks of climate change are considerable at 1 or 2°C above preindustrial level. Global climate change risks are high to very high with global mean temperature increase of 4°C or more ... and include severe and widespread impacts on unique and threatened systems, substantial species extinction, large risks to global and regional food security"

"Climate-change impacts are expected to exacerbate poverty in most developing countries and create new poverty pockets in countries with increasing inequality, in both developed and developing countries."

Food production & security

"All aspects of food security are potentially affected by climate change, including food access, utilization, and price stability (high confidence)."

"Based on many studies covering a wide range of regions and crops, negative impacts of climate change on crop yields have been more common than positive impacts (high confidence)."

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Stormy weather leads to record levels of renewable electricity

  • 27 Mar 2014, 11:30
  • Mat Hope

Vincent van Zeijst

Stormy weather pushed the UK's renewable electricity generation to to record levels at the end of 2013, according to official statistics. However, fossil fuels still made up the largest proportion of the UK's energy mix.

Renewables generated almost 18 per cent of the UK's electricity in the last three months of 2013, with high wind speeds ramping up wind generation.

The figure comes from Department of Energy and Climate Change's monthly energy statistics, which track energy production and consumption between November 2013  and January this year.

Electricity mix by fuel

Electricity generation fell by 3.4 per cent on a year before, the statistics show.

Renewables' share of the overall mix increased to around 18 per cent. Meanwhile the proportion of fossil fuels used to generate electricity decreased slightly, to 61 per cent. Coal power continued to have the highest share: to 36 per cent.

UK electricity mix nov to jan14


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From London to Los Angeles: Tailoring climate policy to meet cities’ needs

  • 17 Mar 2014, 12:30
  • Mat Hope


From London's bright lights to LA's jammed highways, no two cities are alike. And the way they go about cutting their greenhouse gas emissions should be just as unique, a new paper argues.

Cities are responsible for around  75 per cent of the world's carbon dioxide emissions. So if policymakers are going to keep to internationally-agreed climate pledges, they're going to have to cut urban emissions.

But there's no one-size-fits-all solution to reducing a city's emissions, according to a new  paper published in Nature Climate Change today. It looks at 22 cities across the globe, and tries to work out how climate policies can be tailored to fit each city's "unique characteristics".

Comparing emissions

Some cities are much more polluting than others. To work out how to design city-specific climate policies, the researchers first looked at where each city's emissions come from.

The graph below shows the average emissions per person across the 22 cities the study looked at. Each bar shows how much cities emit per resident and is separated by the sector the emissions come from, such as electricity, heating, and transport:

Cities emissions bars

The wealthiest cities tend to have the highest emissions as their residents generally use more energy, the study finds.

As you can see, big US cities such as Denver, Chicago and Los Angeles have much higher emissions per resident than than less wealthy cities in Africa and South America. Likewise, China's sprawling megacities have much higher emissions per capita than their neighbours in Southeast Asia.

The paper identifies three factors in particular which affect each city's emissions: how tightly packed together residents are, how the city's residents get around, and where each city gets its electricity from.


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Thames Barrier’s extraordinary year prompts government to reconsider long term flood plans

  • 13 Mar 2014, 15:00
  • Mat Hope, Ros Donald & Robin Webster

Paul Farmer

Are the Thames' flood defences still up to the job? That's the question on London mayor Boris Johnson's lips.

He's called for a  review of the capitals flood prevention plans after this winter's extreme wet weather pushed the number of times the Environment Agency needed to use London's main flood defence, the Thames Barrier, to unprecedented levels.

As the Thames Barrier breaches the Environment Agency's own 50 closures per year limit for the first time, we look at when it thinks the risk of London flooding might get bad enough for the government to need to take action.

Extreme weather

The Thames Barrier earned its keep this winter, keeping the flood waters at bay more than twice as often as it ever had before.

That's led some - including London's mayor Boris Johnson - to wonder whether the current plans to protect London from flood risk is enough.

Environment Agency data shows the barrier has been closed 173 times to prevent flooding in its history, with over 50 of the closures in the winter of 2013/14. This graph gives an idea of quite how extraordinary this winter was:

Thames barrier closures updated

Source: Data from the Environment Agency, graph by Carbon Brief

The Environment Agency  predicts the flooding risk in this country is likely to increase in the next few decades as a result of climate change. That's concerning, as the Environment Agency says that if the barrier is closed 50 times a year on average or more, new defences will need to be put in place.


The Thames Estuary 2100 Plan lays out a range of options the government can choose to implement if it is concerned about the increased risk of flooding. The accompanying technical document identifies three thresholds that would trigger a decision on new defences.

Threshold 1 is the level at which the current flood defences can no longer cope. Threshold 2 would be passed if the current Thames Barrier and improved defences upriver of the barrier look like they could get overwhelmed. Threshold 3 is set at a point where an improved Thames Barrier combined with increased flood storage and better defences upriver and downriver are no longer enough to keep the floods at bay.

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