Analysis

Remote-control robots reveal why the Antarctic ice sheet is melting

  • 10 Nov 2014, 18:23
  • Robert McSweeney

Research ship | Thomspson et al ( 2014)

At current rates, ice sheet loss will become the most significant contributor to global sea level rise during this century, yet there is still a lot that scientists don't know about the underlying causes. This is partly because Antarctica is such a difficult place to take measurements.

But now robotic underwater gliders are giving scientists new insight into why the Antarctic ice sheet is melting.

Ice sheets

An ice sheet is a huge layer of ice that sits on land. The two on the Earth today are found on Antarctica and Greenland, but in the last ice age there were also ice sheets on North America and northern Europe.

The Antarctic ice sheet spans more than 14 million square kilometers, which is roughly the same size as the US and Mexico put together. The ice sheet also spills out onto the surrounding ocean in the form of ice shelves.

The Intergovernmental Panel on Climate Change (IPCC) estimates that the Antarctic ice sheet is currently losing around 150 billion tonnes of ice per year. One of the main areas of ice loss is from the Antarctic Peninsula, shown in the red rectangle in the map below.

 

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Climate change puts bees and flowering plants out of sync

  • 06 Nov 2014, 17:02
  • Robert McSweeney

Female mining bee | Shutterstock

Warmer spring temperatures are causing bees to hatch earlier, putting them out of sync with the flowers that they pollinate, a new study shows.

The researchers say the study is the first of its kind to show climate change affecting the sort of relationships between species that have evolved together over millions of years.

Successful pollination

Pollination by insects is hugely important for many plants. Insects are responsible for pollinating around 80-85 per cent of commercial crops, for example, amounting to around a third of global food production.

Successful pollination depends on insects being active at the same time the plants are flowering, and many plants have evolved specifically to attract particular insects.

The flowers of the Ophrys sphegodes, or 'Early spider orchid', for example, look like the female of its principal pollinator, the Andrena nigroaenea bee. The orchid even gives off a similar scent as the female.

This fools the male bees into thinking the flowers are females, and so they try to mate with them. Through this process, known as 'pseudocopulation', the bees unwittingly spread the orchid's pollen as they fly from flower to flower.

So far, so sordid. But the new study, published in Current Biology, finds that climate change is affecting this relationship, with implications for spider orchids and other plants that rely on pollinators. 

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Media round-up: The IPCC synthesis report

  • 04 Nov 2014, 16:54
  • Robert McSweeney & Rosamund Pearce

Rajendra Pachauri on Sky News

On Sunday the Intergovernmental Panel on Climate Change (IPCC) published its synthesis report, which summarises the findings of three huge assessment reports. It prompted a flurry of media coverage. Here are some selected highlights.

Broadcast media

  • BBC News discusses the "controversial" recommendation that fossil fuels should be phased out by the end of the century - "a huge undertaking". Since every attempt to negotiate a new climate treaty has failed, and with Paris on the horizon, the BBC asks: "has anything really changed?"

  • With the "glacial" pace of the UN negotiating process,  Channel 4 news asks: can we adapt fast enough? Professor Joanna Haigh argues that climate change has not dropped of the agenda, discusses geoengineering versus preventative measures, and the value of the political process.

channel4news.png

  • In The IPCC report: why it matters, the BBC debates why another report was needed right now. Scientists believe that political leaders are in the process to agree a new climate deal - and they want to give them the most succinct report for this - "It may be the runt of the litter in size, but in political terms, it could turn out to be a real heavyweight".

  • In Climate change action will cost, the BBC broadcasts Ban Ki-moon's speech at the launch of the report.

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Untangling greenhouse gas emissions highlights the importance of carbon dioxide

  • 03 Nov 2014, 20:38
  • Robert McSweeney

Power Plant Emissions | Shutterstock

Efforts to limit climate change should focus on reducing emissions of carbon dioxide over any other greenhouse gas or air pollutant, a new study finds.

Short-lived

You might find you hear about efforts to cut carbon dioxide more than any other greenhouse gas (GHG). This is because carbon dioxide makes the biggest contribution of any of the gases emitted from human activities.

We emit more carbon dioxide than any other GHG, and once in the atmosphere it can stay there for centuries.

But there is also a group of 'short-lived' gases and pollutants that have an important warming effect. These include methane, ozone, hydrofluorocarbons (HFCs) and black carbon (soot).

A recent report by the UN Environment Programme (UNEP) recommended that reducing atmospheric concentration of these gases could "slow the rate of near-term climate change", alongside other benefits such as improving air quality and public health.

Now a study, published in the Proceedings of the National Academy of Sciences, looks at the long-term impact on global temperatures of reducing short-lived gases. And the results suggest that carbon dioxide should remain central to GHG emission cuts.

Influence

Many GHGs and pollutants are emitted from the same sources. Burning coal, for example, releases carbon dioxide, nitrous oxides and black carbon. Cutting coal use to reduce emissions of one gas would mean a reduction in the others as well.

These overlaps between gases and pollutants are significant. For example, 70 per cent of black carbon emissions are related to energy use, such as burning diesel in cars or biomass for cookstoves.

The study looks at the impact on global temperatures of cutting these short-lived gases with, and without, similar reductions in carbon dioxide.

In a scenario of 'no carbon dioxide mitigation', global temperatures would rise by over five degrees by 2100, but cutting emissions of methane, HFCs and black carbon would reduce this rise by around 0.9°C.

However, when carbon dioxide mitigation was included and global temperatures only rose by just over two degrees, the influence of reducing the other pollutants reduced to around 0.5°C. You can see the difference in the figure below.

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Carbon Brief’s guide to the Intergovernmental Panel on Climate Change’s fifth assessment report

  • 03 Nov 2014, 09:45
  • Carbon Brief staff

Night earth | Shutterstock

The Intergovernmental Panel on Climate Change (IPCC) has just completed a major review of global climate research - its fifth assessment report (AR5).

The report is split into three sections. The first two instalments cover the science and impacts of climate change. The third part looks at policies to cut global greenhouse gas emissions. The IPCC also produces a synthesis report, drawing all the research together.

We've covered each instalment in detail. Here's a catalogue of Carbon Brief's summaries, guides, and analyses of the IPCC's fifth assessment report.

Working group 1: The science

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The IPCC’s untapped resource: the frequently asked questions

  • 03 Nov 2014, 09:41
  • Robert McSweeney

Answers | Shutterstock

This Sunday, the Intergovernmental Panel on Climate Change (IPCC) will publish its latest Synthesis Report, a non-technical summary of three huge Assessments Reports.

But there is another easily-accessible IPCC resource that has already been published and is often overlooked: the IPCC's Frequently Asked Questions.

So what information does an FAQ written by the world's top climate scientists provide?

Here are some of the questions they cover:

- FAQ 1.1: If understanding of the climate system has increased, why hasn't the range of temperature projections been reduced?

- FAQ 2.1: How do we know the world has warmed?

- FAQ 2.2: Have there been any changes in climate extremes?

- FAQ 3.1: Is the ocean warming?

- FAQ 3.2: Is there evidence for changes in the Earth's water cycle? 

- FAQ 3.3: How does anthropogenic ocean acidification relate to climate change?

- FAQ 4.1: How is sea-ice changing in the Arctic and Antarctic? 

- FAQ 4.2: Are glaciers in mountain regions disappearing?

- FAQ 5.1: Is the Sun a major driver of recent changes in climate? 

- FAQ 5.2: How unusual is the current sea level rate of change?

- FAQ 6.1: Could rapid release of methane and carbon dioxide from thawing permafrost or ocean warming substantially increase warming? 

- FAQ 6.2: What happens to carbon dioxide after it is emitted into the atmosphere? 

- FAQ 7.1: How do clouds affect climate and climate change?

- FAQ 7.2: How do aerosols affect climate and climate change?

- FAQ 7.3: Could geoengineering counteract climate change and what side effects might occur?

- FAQ 8.1: How important Is water vapour to climate change?

- FAQ 8.2: Do improvements in air quality have an effect on climate change?

- FAQ 9.1: Are climate models getting better, and how would we know? 

- FAQ 10.1: Climate is always changing. How do we determine the causes of observed changes?

- FAQ 10.2: When will human influences on climate become obvious on local scales?- FAQ 11.1: If you cannot predict the weather next month, how can you predict climate for the coming decade?

- FAQ 11.2: How do volcanic eruptions affect climate and our ability to predict climate?

- FAQ 12.1: Why are so many models and scenarios used to project climate change?

- FAQ 12.2: How will the Earth's water cycle change? 

- FAQ 12.3: What would happen to future climate if we stopped emissions today? 

- FAQ 13.1: Why does local sea level change differ from the global average? 

- FAQ 13.2: Will the Greenland and Antarctic ice sheets contribute to sea level change over the rest of the century?

- FAQ 14.1: How is climate change affecting monsoons?

- FAQ 14.2: How are future projections in regional climate related to projections of global means?

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Rising temperatures will delay disease reduction in China, study shows

  • 02 Nov 2014, 18:01
  • Robert McSweeney

Child washing hands | Shutterstock

Efforts to reduce water-related diseases in China will be hampered by climate change, a new study finds.

Despite continued improvement in access to clean water and sanitation across China, rising temperatures could set back progress in reducing infectious diseases by as much as seven years by 2030.

Warmer temperatures

According to the UN, China has made significant progress on reducing water-related diseases in recent years. It has already met its Millennium Development Goal to halve the number of people without access to safe drinking water.

Recent decades have seen a huge drop in cases of water-related diseases in the country. Between 1990 and 2010 deaths from diarrheal diseases fell by 94 per cent. Malaria and Japanese encephalitis, both spread by mosquitoes that breed in water, fell by over 60 per cent and over 80 per cent, respectively .

However, a study published in Nature Climate Change suggests further progress on water-related diseases will be stunted by climate change.

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Briefing: What's new and interesting in the IPCC synthesis report

  • 02 Nov 2014, 10:00
  • Roz Pidcock

Clouds farmland | Shutterstock

The world has received the clearest message yet on how humans are changing the climate. Delegates from 195 countries gathered in Copenhagen this week to add their seal of approval to a 100-page "synthesis report". It's the final instalment in a four-part series from the UN's Intergovernmental Panel on Climate Change (IPCC).

The synthesis report condenses the IPCC's three other major reports on different aspects of climate change into one concise document. While that means some parts of it may sound familiar, there are some new and different sections as well. Here's our assessment of what's new, as well as a look at the report's main conclusions.

Warming continues unabated

Evidence that the climate is warming is unequivocal, the IPCC says. Each of the last three decades has been warmer than any previous one since 1850, and the world has warmed by about 0.85 degrees since then.

Today's report explains how the rate of surface warming varies from decade to decade, noting that warming since 1998 has been a third to half of the average since the 1950s. But, it adds:

"Even with this reduction in surface warming trend, the climate system has very likely continued to accumulate heat since 1998".

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The IPCC synthesis report: A summary for everyone

  • 02 Nov 2014, 10:00
  • Roz Pidcock

Daniel Julie

Today marks the release of an important document in the climate science world.

At 10 am this morning, the group of experts tasked by the United Nations with assessing the state of the climate released a major report on how and why it is changing, as well as what we can do about it.

Covering everything from declining sea ice to harnessing energy from the wind, the 100-page document has been hailed as an  essential "handbook" on climate change.

It connects the dots between three reports released by the Intergovernmental Panel on Climate Change (IPCC) over the past year, each looking at a different aspect of climate change.

Totting up the risks

Greenhouse gas emissions from humans are the highest in history, the first in the series of reports told us last year. Greenhouse gases trap heat in the atmosphere. Carbon dioxide and other greenhouse gases are released when we burn fossil fuels like coal, oil and gas.

As a result the oceans, land and atmosphere are warming, snow and ice cover is melting, our weather is getting more extreme and sea levels are rising.

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Why the IPCC synthesis report is necessary but not sufficient to secure a response to climate change

  • 31 Oct 2014, 13:45
  • Simon Evans

Factory chimneys | Shutterstock

On Sunday 2nd November, the Intergovernmental Panel on Climate Change (IPCC) will publish its latest synthesis report, distilling the latest knowledge on what UN chief Ban Ki-Moon has  called the greatest threat ever faced by humanity.

The synthesis report will wrap up the IPCC's fifth assessment (AR5) of climate change. It draws together information from the IPCC's reports on the science of climate change, climate impacts and the  ways climate risks can be addressed.

It takes a mammoth collective effort on the part of scientists, economists and policymakers to produce these IPCC reports. Is it worth it?

We've collected a range of views on the need for, and wider significance of, the IPCC's work. These suggest it remains a necessary but not sufficient part of the job of addressing climate change.

The synthesis report is necessary

Does the world need an IPCC, asks former IPCC chair and former scientific adviser to the UK government Bob Watson. "My answer would be absolutely yes," he says. "I think it's critically important the IPCC does routinely report back on what we know."

The synthesis report collects together scientific opinion on the technical and socio-economic aspects of the causes of climate change, the risks it poses and the options for adaptation and mitigation. It is unique in taking such a wide ranging and considered view of climate.

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