Remote-controlled submarines reveal Antarctic sea ice is thicker than previously thought

  • 24 Nov 2014, 16:14
  • Robert McSweeney

WHOI UAV | Guy Williams

New research sees scientists using remote-controlled submarines to create 3D maps of Antarctic sea ice. And the results suggest sea ice is thicker than previously thought.

The area covered by Antarctic sea ice appears to be slightly growing each year, the reasons for which are proving hard to pin down. Today's research adds another dimension to unravelling the complex goings-on around the South Pole.

Measuring ice thickness isn't easy

Scientists have been monitoring changes at Earth's poles for decades now. But the harsh conditions of the Antarctic make it difficult to get good measurements of the sea ice that surrounds the vast continent.

How and why Antarctic sea ice thickness is changing "remains one of the great unknowns in the climate system," says Dr Ted Maksym of the Woods Hole Oceanographic Institution (WHOI) in Massachusetts.

While satellites are very good at measuring the extent, or area, of sea ice covering the ocean, they struggle when it comes to ice thickness. Satellite measurements can't distinguish between ice and the snow lying on top of it, which makes it harder for scientists get accurate readings of its true depth.

Scientists can also make estimates of thickness from visual observations or by drilling into the ice itself. But these approaches are hampered by thick sea ice during winter and spring, which prevents ships from accessing parts of the Antarctic coast.

To overcome these limitations, Dr Maksym and his colleagues deployed 'Autonomous Underwater Vehicles (AUVs)', which are specially-designed unmanned submarines that measure ice thickness to within 10 centimetres.

The data from these submarines, published in  Nature Geoscience, suggests that Antarctic sea ice is thicker than previously thought.

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World Bank: ending poverty might become impossible because of climate change

  • 24 Nov 2014, 13:54
  • Carbon Brief Staff

Lifting the world's poorest out of extreme poverty may become impossible because of climate change, according to the  World Bank's new Turn Down the Heat report.

It looks at the consequences of warming in three regions: the Middle East and North Africa, Latin America and the Caribbean, and eastern Europe and central Asia. The World Bank says these areas are already feeling the effects of 0.8 degrees of warming above pre-industrial temperatures.

If warming reaches four degrees by the end of the century, "unprecedented" heatwaves could affect the large majority of the land area of the Middle East, North Africa and Latin America in the coming decades. This new climate normal could  cut crop yields by up to 70 per cent while increasing flood risks by a third in some regions and pushing up the incidence of drought by a fifth in others.

The shocks and stresses to come could undermine poverty reduction, push new groups into  poverty, lead to  population migrations and even increase the  risk of conflict, the report says.

Poverty reduction

World Bank president Jim Yong Kim writes in a foreword to the report:

"Ending poverty, increasing global prosperity and reducing global inequality, already difficult, will be much harder with two degrees of warming, but at four degrees there is serious doubt whether these goals can be achieved at all."

Today, 1.2 of the world's 7 billion people live in extreme poverty.

Unfortunately the World Bank says some of the negative impacts of climate change may now be unavoidable because the world is "locked into" warming of close to 1.5 degrees above pre-industrial levels. Even very ambitious attempts to limit emissions  cannot change this.

But averting the worst projected climate impacts of a four degrees world remains technically, economically and politically feasible if global leaders are prepared to take tough choices now, Kim says.

Regional analysis

The report was prepared for the World Bank by the Potsdam Institute for Climate Impact Research and Climate Analytics, a Potsdam-based climate NGO and follows similar reports published in  2012 and  2013.

We've taken a look at the 300-page report's detailed findings for the Middle East, Latin America and Europe and central Asia, to see what challenges and changes a climate-changed future might hold.

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Tackle air pollution to kickstart climate action, says new study

  • 19 Nov 2014, 18:00
  • Roz Pidcock

Air pollution is a huge problem worldwide, killing millions of people each year. Further warming will only increase the size of the problem, according to a Nature article today.

It's time efforts to curb soot, ozone and other pollutants in the atmosphere got more attention at an international level, the researchers argue.

Getting serious about air pollution could provide the impetus needed to tackle climate change more effectively.

Airborne killers

Methane, ozone, nitrogen dioxide and soot (or black carbon) all contribute to poor air quality.

Air pollution is already the  leading environmental cause of ill-health, leading to about seven million premature deaths each year from respiratory and circulatory illnesses.

Earlier today, the European Council  ruled the UK must take urgent action to address dangerous levels of air pollution. A number of major cities, including London, are lagging behind targets to reduce nitrogen dioxide to legal limits by the January 2015 deadline.

The burden of ill-health is  likely to increase in cities by mid century, as air pollution interacts with further greenhouse gas warming, research shows.

Compounds Of Concern _Schmale

Impacts of common air pollutants for human health, the climate and agriculture. Source: Schmale et al. (2014)

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How small volcanic eruptions may have slowed surface temperature rise

  • 19 Nov 2014, 17:20
  • Robert McSweeney

Tungurahua eruption | Shutterstock

Scientists have been underestimating the influence of small volcanic eruptions on the climate system, a new study argues.

The findings could help explain why recent warming at the Earth's surface has been slower than in previous decades, the researchers say.

A cataclysmic event

In June 1991 Mount Pinatubo in the Philippines erupted, sending a cloud of ash, dust and sulphur dioxide 35 kilometers into the atmosphere.

That sulphur dioxide combined with oxygen and water to form sulphuric acid aerosols. These particles reflected sunlight and encouraged clouds to form, cooling parts of the world by up to 0.4°C for two years after the eruption.

Volcanic eruptions are rated from zero to eight on a scale of explosivity, measured by the amount of ash and debris they produce. The Pinatubo eruption was rated as a five, or 'cataclysmic'.

While the world hasn't seen such a huge volcanic eruption since, on average there is one small eruption somewhere in the world every week. A new study, published in Geophysical Research Letters, finds that these smaller eruptions may together have a bigger impact on global climate than previously thought.

Pinatubo _ash _plume _910612

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Why feeding more people doesn't have to be at the expense of the climate

  • 18 Nov 2014, 16:14
  • Robert McSweeney

Wheat | Prof. Yantai Gan

The world is on course to produce more wheat this year than ever before. Yet as supply rises to meet demand, so do the carbon emissions from growing and harvesting the crop.

Now a 25-year long field experiment in Canada shows that growing wheat can actually take up more carbon than it releases. Meeting demand for food doesn't have to mean more carbon emissions, the study's lead scientist tells us.

Wheat is in demand

Wheat is the third most-grown cereal crop in the world, after maize and rice. Demand for major cereal crops such as wheat is expected to increase by 70 percent by 2050.

In the UK, around two million hectares of land are used to grow wheat, with the harvested crop worth around £1.2 billion. But wheat accounts for 30 per cent of emissions from growing the crops we eat, estimates WWF.

Fuel burned in tractors used to farm land releases carbon dioxide, as does producing and using fertilisers. These emissions typically outweigh the amount of carbon dioxide the crops absorb as they grow.

Now a new study by Canadian researchers, published in Nature Communications, finds that with some changes to farming practices, growing wheat can actually remove more carbon dioxide from the atmosphere than it produces.

Little field on a prairie

The US and Canada are the third and fifth largest producers of wheat in the world. Between them they harvested around 90 million tons of wheat last year. Most of this is grown in the 'wheat belt', a vast area of the North American prairies that stretches across much of central US and Canada.

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How an IPCC graph linked fossil fuel use to climate change, and why it led to a heated debate

  • 18 Nov 2014, 12:45
  • Roz Pidcock

Earlier this month, the Intergovernmental Panel on Climate Change (IPCC) released a major new report, summarising scientific knowledge on climate change.

It contained something of a milestone in IPCC history - a chart linking greenhouse gas concentrations to fossil fuel emissions, rising global temperatures and sea level.

That might sound fairly innocuous. But some countries argued against its inclusion. So why was a figure outlining the well-understood link between carbon dioxide and climate change contentious?

Connecting the dots

The new figure charts the growth of atmospheric greenhouse gases over the industrial period, alongside rising emissions from fossil fuels and changes in global temperature and sea levels.

Synthesis Report _1point 1D

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Imported meat comes with a climate cost, new study warns

  • 17 Nov 2014, 15:03
  • Robert McSweeney

Cow and wind turbines | Shutterstock

A lot of the meat we eat is produced in a different country from the one we live in. A new study finds that greenhouse gas emissions from the beef, pork and chicken traded across borders have risen by 19 per cent in the past 20 years.

Not only might this affect diets of the climate-conscious, but a trend towards eating meat produced in a different country could make monitoring countries' individual emissions a far trickier task, say the researchers.

Livestock emissions

Carbon dioxide is the biggest contributor to climate change, but other greenhouse gases such as methane and nitrous oxide play a role too. The methane and nitrous oxide produced by livestock, such as cows, pigs and chickens, account for around nine per cent of all greenhouse gases emitted worldwide.

When you include methane and nitrous oxide emissions from transporting the animals and producing their feed, this proportion rises to 18 per cent.

A new study, published in Environmental Research Letters, finds that although the majority of meat is eaten in the country where it's produced, more and more meat is being exported.

So which country should be held responsible for the greenhouse gas emissions? The one where the meat is produced or the one where it's consumed?

The researchers say the growing demand for internationally-traded meat makes it harder to regulate emissions from farming.

Emissions from trade slipping through the cracks

All existing national or international policies to limit greenhouse gases take account of emissions from within specific countries only. So if the UK imports a tonne of beef, for example, the greenhouse gas emissions from producing it are not counted in our inventory.

You might think the emissions would be counted by the country producing the beef, but that might not be the case. The researchers say it's increasingly likely that meat is being imported from developing and emerging nations, which often have less stringent accounting of greenhouse emissions.

So the emissions from that tonne of beef may not be counted by either country, and instead may just 'leak' between the gaps in the system, say the researchers.

Beef the worst emitter, but others are catching up

Of the meat traded from one country to another, the study finds beef makes the biggest contribution to emissions, responsible for around three-quarters of the GHGs produced.

The research takes account of methane produced as livestock digest food (yes, farting) and the methane and nitrous oxide released as manure decomposes.

Emissions from traded pork (20 per cent) and chicken (six per cent) production are much lower by comparison, but are growing much more quickly. Between 1990 to 2010, the emissions from traded beef grew by around four per cent, while those from pork and chicken grew by 81 per cent and 360 per cent, respectively. You can see this in the charts below.

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US lightning strikes to increase under climate change

  • 13 Nov 2014, 19:25
  • Robert McSweeney

Lightning over field | Shutterstock

Climate change is likely to increase the number of lightning strikes, according to a study that models the effect of a warmer climate on lighting in the US.

Lightning already strikes the US about 25 million times each year, causing dozens of deaths and millions of dollars' worth of damage from fires. The study finds the number of strikes could increase by around 50 per cent through the 21st century.

Static electricity

When static electricity builds up in large storm clouds it can discharge as lightning, either extending into the air, within the cloud itself, or striking the Earth's surface. The electricity is generated as water droplets and ice crystals bump into each other as they rise and fall within the cloud.

There are around 25 million lightning strikes in the US every year, mostly on the eastern side of the country. The map below plots them.Romps Et Al (2014) Fig1

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Six years worth of current emissions would blow the carbon budget for 1.5 degrees

  • 13 Nov 2014, 11:00
  • Roz Pidcock and Rosamund Pearce

It will take just six years of current emissions to exhaust a carbon budget that would give a good chance of keeping global warming below 1.5 degrees Celsius, based on figures from the Intergovernmental Panel on Climate Change (IPCC).

The IPCC's new budget,  revealed earlier this month, calculates the remaining amount of carbon dioxide humans can emit and still hope to cap global warming at less than 1.5 degrees Celsius above preindustrial levels.

Limiting warming to 1.5 degrees has become a political rallying call for some nations and Non-Governmental Organisations (NGOs).

The IPCC's calculations suggest hopes of preventing temperatures from ever crossing the 1.5 degree threshold are slim to none. But the IPCC highlights that options to temporarily exceed the target and return to lower temperatures later in the century could still be on the table.

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Warmer temperatures and more acidic oceans put crabs into survival mode

  • 13 Nov 2014, 08:43
  • Robert McSweeney

Porcelain crab | Adam Paganini

The combined effect of rising temperatures and a more acidic ocean will make it harder for seashore crabs to grow and reproduce, a new study finds.

The results suggests that other marine species could be affected too, the researchers say.

Basic functions

The oceans absorbs around 30 per cent of the carbon dioxide we emit into the atmosphere. When carbon dioxide dissolves in water, carbonic acid is produced, which makes the oceans more acidic. The oceans have become around 26 per cent more acidic since the industrial revolution and this is projected to increase further under all scenarios of the Intergovernmental Panel on Climate Change.

New research, published in The Journal of Experimental Biology, studies the impact of ocean acidification and higher air temperatures on the porcelain crab, which lives in rocky shorelines on the coasts of the Indian and Pacific Oceans.

The results show that warmer, more acidic conditions mean the crabs have to put a greater proportion of energy into the basic functions of living and breathing, leaving less for anything else.

This could be an indicator for other species in the 'intertidal zone', or seashore, too. As co-author, Professor Jonathon Stillman, explains: "future intertidal zone animals may experience reduced rates of growth, behavior, or reproduction."

High- and low-tides

While previous studies have tested the impact of constant high temperatures and acidity on sea creatures, this isn't typical of the conditions on the seashore.

Air temperatures in the intertidal zone can change by 20°C within six hours, while acidity levels can vary between day and night and from one season to the next. This study tests temperature and acidity that peak and fall during the day.

In order to test the crabs under these conditions, researchers constructed a specially-designed aquarium, which could simulate high- and low-tide as well as different temperatures and acidity.

They simulated 'low-tide' in the aquarium for seven hours each day, reducing the water and increasing the air temperature. Then for five hours of 'high-tide' they submerged the crabs with water and brought the air temperature back down. They tested three scenarios of higher temperature and higher acidity (no change, moderate change and extreme change).

Combined effects

After two and a half weeks in those conditions, the researchers tested the metabolic rate and thermal tolerance of the crabs.

The findings show the combination of higher temperatures and more acidic water cause the crabs' metabolic rate to fall by as much as 25 per cent. You can see this by the green line in graph A below. The metabolism of the crabs slowed down, leaving them less energy to use in finding food, reproducing, or growth.

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