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Surface warming ‘hiatus’ could stick around for another decade, say scientists

  • 21 Aug 2014, 19:00
  • Roz Pidcock

A flip-flopping natural fluctuation in the Atlantic is behind a recent slowdown in surface warming - and it's not due to reverse for another ten years, according to new research.

The theory outlined in a paper  published today in the journal Science disagrees with other research, which pins the blame for the so-called "pause" on changes in the Pacific.

We talked to some other scientists working in the field - and they don't seem convinced.

Puzzle solving

Scientists know greenhouse gases are driving up  global temperature. But data on land and  the surface of the ocean shows  slower than expected warming in the last 15 years or so.

Periods of slower and faster warming  aren't unusual. Scientists say the main reason we're seeing one now is because more heat is finding its way to the  deeper ocean, rather than staying at the surface.

But which ocean? Knowing where the heat is ending up might help scientists predict how long the hiatus will last.

Where Is Global Warming Going _infographic

More than 93 per cent of the heat reaching earth's surface goes into the oceans. Just 2.3 per cent stays in the atmosphere. Source: Skeptical Science

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Greenland and Antarctic maps reveal “unprecedented” ice loss

  • 21 Aug 2014, 17:02
  • Robert McSweeney

Greenland Iceberg | Shutterstock

A series of maps published this week show Greenland and Antarctica are losing more ice than at any time since satellite records began.

Scientists found the two vast ice sheets are losing a total of 500 cubic kilometers of ice per year, contributing to rising global sea levels.

Ice loss

The researchers used data from the European Space Agency's  CryoSat - a satellite that passes over the earth at 700 kilometers above the surface and measures the thickness of polar ice.

The satellite was launched in 2010 and has been collecting data on sea ice and ice sheets ever since. By comparing data with other satellite missions, scientists can see how quickly the ice sheets are changing.

The study, just published in the journal  The Cryosphere, reveals that since 2009, the volume of ice loss has tripled in West Antarctica and more than doubled in Greenland. This is the highest rate of ice loss since satellite records began 20 years ago.

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Climate change a ‘major challenge’ to South Asia’s economic development - report

  • 20 Aug 2014, 15:50
  • Mat Hope

CC 2.0

India, Sri Lanka, Bangladesh, Bhutan, the Maldives and Nepal will face "major challenges" as the impacts of climate change start to bite, according to a new report.

The Asian Development Bank's (ADB)  163-page analysis outlines how warmer temperatures and rising seas could hit South Asia's varied economies, home to nearly 1.5 billion people. It concludes that the "impacts of climate change are likely to result in huge economic, social and environmental damage to South Asian countries".

Climate impacts

ADB uses the Intergovernmental Panel on Climate Change's (IPCC) emissions scenarios to model potential climatic changes in South Asia between now and 2100. It then uses an economic model to estimate how the climate impacts may affect the region's development.

The analysis was conducted prior to the release of the three instalments of the IPCC's fifth assessment report - published between November 2013 and April this year - so uses data from the fourth report, released in 2007.

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How a warmer Arctic could lead to colder winters in Britain

  • 20 Aug 2014, 15:14
  • Robert McSweeney

Arctic North Pole | Shutterstock

When you're chipping ice from your car windscreen or sheltering from the snow on a windswept platform, you might find yourself wondering how climate change fits in with the flurry of cold winters we've seen in recent years.

One theory suggests very cold winters in the northern hemisphere could be linked to rapidly increasing temperatures much further north - in the Arctic. A  new paper outlines three ways scientists think the two could be linked.

Rapid Arctic warming

Temperatures in the Arctic have been increasing almost  twice as fast as the global average. This is known as  Arctic amplification. As Arctic sea-ice shrinks, energy from the sun that would have been reflected away is instead absorbed by the ocean.

From 2007 to 2013, we've seen some of the lowest summer sea ice levels since records began, as shown in the graph below. This has coincided with a number of extreme cold and wet events across the mid-latitudes of the northern hemisphere, including the cold start to 2013 in the UK and the record low temperatures in the US and Canada during the 2013-14 winter.

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Factcheck: Is climate change linked to recent UK flooding?

  • 20 Aug 2014, 14:15
  • Roz Pidcock

This morning's  Times claims new research says the increase in flooding in Britain in recent times is due to urban expansion and population growth, rather than climate change.

According to the piece, this "does not agree" with warnings from scientists that climate change can be linked to recent flooding. But a quick look at the science shows a combination of land use and climate change is upping the risk of flooding in the UK.

"Misquote"

The Times story is based on a new study from the University of Southampton. The number of reported flooding events in the UK grew between 1884 to 2013, according to the research.

But although the number of reported floods went up, it's mainly down to more people being exposed, the authors tell us. During that time, the population grew from 38.2 to 59.1 million.

If you remove the effect of population rise, there's no longer a clear increase in the number of reported flooding events, the report suggests. This is presumably where the Times draws its conclusion that the new research "rules out a link between last year's winter flooding and climate change".

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Why scientists need public backing to engineer the climate

  • 19 Aug 2014, 12:35
  • Mat Hope

PiccoloNamek

As global greenhouse emissions rise, scientists want to research the possibility of engineering the climate to avoid the worst impacts of global warming.

But the public has so far been wary of such schemes. So the so-called geoengineers are planning to make a declaration they hope will be the first step to getting a "social license" to operate.

The world's most prominent geoengineering researchers are meeting in Berlin this week to discuss the the field's progress. Attendees have been asked to provide feedback on a draft document styled as  the Berlin Declaration, released by  VICE this morning.  

It seeks to clarify geoengineering's governing principles, and quell public concerns. But does it go far enough?

Building blocks

A lot of climate engineering sounds a bit sci-fi - from drawing carbon dioxide out of the oceans by dumping iron filings in the sea, to putting mirrors in space to reflect sunlight away from earth. We've gone into much more detail, here.

The Intergovernmental Panel on Climate Change (IPCC) takes geoengineering seriously, even if it gets a relatively small amount of attention in its reports. The panel is also eager to  emphasise the technique's risks.

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‘Hiatus’ in surface warming is upping the odds of UK cold winters, say scientists

  • 17 Aug 2014, 20:20
  • Roz Pidcock

If you follow climate science, you'll be familiar with the so-called surface warming "hiatus". It's the fact that temperatures at earth's surface haven't climbed as much as expected in the last 15 years.

Now a  new paper published in Nature Climate Change says the slowdown in surface warming could be behind a spell of colder than average winters in the UK recently.

Screen Shot 2014-08-17 At 20.07.46

UK winters in 2009/10 were two degrees and 1.3 degrees Celsius below the 1971-2010 long term average, respectively. The 2012/13 winter was 0.4 degrees below the 1981-2010 average. Source: Met Office

Cause of the pause

Scientists know greenhouse gases are driving up  global temperature. But data on land and from the surface of the ocean shows  slower than expected warming in the last 15 years or so.

Scientists say periods of slower and faster warming  aren't unusual. Most of  why we're seeing one now is down to natural climate cycles causing the surface of the  Pacific Ocean to cool.

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Climate scientists dub this year’s El Niño “a real enigma”

  • 04 Aug 2014, 14:40
  • Roz Pidcock

Last month, forecasters were predicting with  90 per cent certainty we'd see an El Niño by the end of the year, driving severe weather patterns worldwide. But with little sign so far of the ocean and atmospheric changes scientists expected, those odds have dropped off quite a bit.

We'll probably still see an El Niño before the year's out but it's unlikely to be a strong one, scientists are saying.  

What is an El Niño?

Every five years or so, a change in the winds causes a shift to warmer than normal ocean temperatures in the  equatorial Pacific Ocean - a phenomena known as El Niño.

Together, El Niño and its cooler counterpart La Niña are known as the El Niño Southern Oscillation (ENSO). Between them, they're responsible for most of the fluctuations in global weather we see from one year to the next.

ENSO

Sea surface temperature during El Niño (left) and La Niña (right). Red and blue show warmer and cooler temperatures than the long term average. [Credit: Steve Albers, NOAA]

 

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Air pollution and climate change could mean 50 per cent more people going hungry by 2050, new study finds

  • 30 Jul 2014, 12:20
  • Roz Pidcock

The combination of rising temperatures and air pollution could substantially damage crop growth in the next 40 years, according to a new paper. And if emissions stay as high as they are now, the number of people who don't get enough food could grow by half by the middle of the century.

Burning question

Feeding the world's rapidly growing population is a serious concern.

Research shows  rising temperatures are likely to lead to lower crop yields. Other work suggests air pollution might reduce the amount of food produced worldwide. But nobody has considered both effects together, say the paper's authors.

The two effects are closely related as warmer temperatures increase the production of ozone in the atmosphere, the paper explains. 

The  new study looks at global yields of the four principle food crops - wheat, rice, corn and soybean - and how they're expected to change by 2050 under different levels of future emissions.

Together, these provide nearly  60 per cent of all the calories consumed by humans worldwide.

Global losses

The maps below show some of the results.

The top panel shows an optimistic scenario in which greenhouse gases stabilise at 630 parts per million (ppm) by 2100. For reference, we're at about 400 ppm now.

The team compared this with what might happen if greenhouse gases continue to rise as rapidly as they are now. That's the bottom panel.

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Does British belief in climate change really go up and down? A look at 14 polls

  • 29 Jul 2014, 15:30
  • Ros Donald

Newspapers love to cover surveys that show  belief in climate change has  risen or fallen. But how much can polls really tell us about what the UK public believes when it comes to climate change? We surveyed 14 polls to try and understand what's happening. 

We looked at polls by the  Guardian, the Sunday Times, the  Department of Energy and Climate Change (DECC),  Carbon Brief ( twice), the  UK Energy Research Council (UKERC) and Ipsos Mori.  

The polls were released between 2009 and 2014, but UKERC's poll includes earlier results from surveys in 2005 2010 and  2012

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