Analysis

Beneath the waves: How the deep oceans have continued to warm over the past decade

  • 02 Feb 2015, 16:00
  • Roz Pidcock

Alongside the  news today that  14 out of the 15 warmest years at Earth's surface have been in the 21st century, a new paper shows just how much the deep oceans are warming, too.

Between 2006 and 2013, the oceans took up a vast amount more heat than the atmosphere. But you have to look below the surface to find it, says the paper in Nature Climate Change. Using the latest ocean-observing technology, the authors find more than half the heat lurks in the deep sea, below 700m.

Trapping heat

Scientists have known for centuries that greenhouse gases in the atmosphere trap heat and warm the planet. Today, scientists use satellite measurements to monitor how much of the Sun's energy enters Earth's atmosphere. A different set of measurements tells them how much finds its way out again.

The difference between those numbers is increasing, which means the Earth is  trapping more heat than it used to. And that means the planet  must be warming.

And since scientists know the oceans absorb more than 90 per cent of the heat the planet traps, it makes sense that the oceans should be warming, too.

Oceanheatadjustedocean 2logo

Source: Rosamund Pearce, Carbon Brief

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UN World Meteorological Organisation ranks 2014 as hottest year on record

  • 02 Feb 2015, 09:00
  • Roz Pidcock

Last year was most likely the warmest year on record, the World Meteorological Organisation (WMO) announced today. Global surface temperature in 2014 was 0.57 degrees Celsius above the 1961-1990 average, nominally beating 2010 and 2005 to the top spot.

In the last few weeks, the world's four main meteorological agencies have all announced that 2014 topped the charts as one of the hottest year on record. Today, the WMO made it official.

Fourteen of the fifteen warmest years on record have now all occurred in the 21st century, today's report notes.

Taking the top spot

The WMO is the United Nations' specialist weather and climate agency. It does its own analysis about this time every year, combining three major global datasets into one definitive one.

Global -temp -2014-6

Global surface temperature anomaly in 2014 from the three major agencies, the average from the World Meteorological Agency (WMO) and the Japan Meteorological Agency. All figures relative to the 1961-1990 average. Source: Rosamund Pearce, Carbon Brief

In mid-January, NASA and the US National Oceanic and Atmospheric Administration (NOAA) issued a  joint statement saying 2014 was the warmest year since 1880.

Last week, the UK Met Office and the University of East Anglia  released their joint data, announcing that 2014 tied with 2010 as the hottest year on record.

A less well-known dataset, produced by the Japan Meteorological Agency (JMA), became the first to confirm that 2014  had taken the top spot in their record earlier in January.

 

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Met Office puts high odds on the next few years being warmer than 2014

  • 30 Jan 2015, 14:20
  • Roz Pidcock

Expect to see more global temperature records tumble over the next few years, suggests the Met Office's new forecast. Global average surface temperatures during 2015 to 2019 are expected to stay high, with a good chance of beating 2014 for the hottest year on record.

Every year the Met Office releases what's called a "decadal forecast". It's designed to give us an idea of what we can expect in the next few years.

It's new forecast, released online this week, says global temperature out to 2019 is expected to be in the range of 0.18 and 0.46 degrees Celsius above the long-term average.

This means we're likely to see the mercury climb higher than in 2014, which saw a global temperature of 0.26 degrees Celsius above the long-term average.

Decadal forecasts

Decadal forecasts, also known as "near-term" forecasts, take into account natural fluctuations in the climate, as well as human influences.

The Met Office predicts global temperature over the next five years will be between 0.18 and 0.46 degrees above the 1981-2010 average. That's 0.76 to 1.04 degrees above pre-industrial temperature.

The graph below shows the new Met Office forecast (blue shading) and real-world surface temperatures (black line), including the most recent data for 2014.

Met Office Decadal 2015Observed global surface temperature (black line) and Met Office decadal forecast for 2015-2019 (blue shading) relative to 1981-2010. Previous predictions are shown in red. 22 model simulations from CMIP5 that have not been initialised with current observations are shown in green. Source: Met Office decadal forecast  2015-2019

The new forecast slightly edges up global temperatures expected over the next few years, compared to last year's forecast for 2014 to 2018. That one predicted global temperatures between 0.18 and 0.43 above the long-term average. But the difference is very small.

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New US poll shows gap between scientists, the public, and politicians on climate change

  • 30 Jan 2015, 12:30
  • Mat Hope

Crowd outside Congress | Shutterstock

The US Congress  set up a showdown with the Barack Obama yesterday over the approval of the  controversial Keystone XL oil sands pipeline.

Most members of Congress argue it's necessary for the country's energy security. The president is concerned about the impact that extracting, transporting, and burning the oil could have on climate change.

New polling data shows the vast majority of the US's scientists and growing numbers of the public share the president's concern about how human activity may impact climate change. It suggests that the views of politicians are increasingly at odds with the country's climate scientists.

Causes of climate change

Growing numbers of US adults attribute climate change to human activities, new data from the  Pew Research Centre shows. But there's a big discrepancy between the public, politicians, and scientists' views on climate change.

Screen Shot 2015-01-30 at 11.04.43.png
Sources: Public and scientists,  Pew Research Centre. Congress, the  Centre for American Progress. Graph by Carbon Brief.

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UK flooding pushes public acceptance of manmade climate change to five-year high

  • 29 Jan 2015, 00:01
  • Robert McSweeney

Berkshire floods 2014 | Shutterstock

There is growing public acceptance of the human contribution to climate change, according to a new study published today. The latest results from a national survey show public agreement that humans are causing climate change is at its highest level for 5 years.

The researchers also find that those affected by the UK winter floods in 2013-14 were significantly more likely to be concerned about climate change than those that weren't affected.

Public acceptance

A year on from the major winter flooding in the UK, the new study led by Cardiff University sheds new light on public perception of climate change. Researchers interviewed 1,002 people across the country about their views on climate change and the floods.

The results of the survey show almost nine in 10 respondents said the world's climate is changing (88 per cent), and more than eight in 10 said human activity was at least partly the cause (84 per cent). This represents the highest level of acceptance that the climate is changing since surveys began asking the question in 2005. More than a third (36 per cent) said that climate change is mainly or entirely caused by humans, which is the most agreement on the human impact on climate change since the question was first included in comparative surveys in 2010.

Capstick Et Al (2015) Is The Climate Changing

Responses from this and previous surveys to the question 'As far as you know, do you personally think the world's climate is changing?'. Source: Capstick et al. (2015).

Capstick Et Al (2015) Causes Of Climate Change

Responses from this and previous surveys to the question 'Thinking of the causes of climate change, which best described your opinion?'. Source: Capstick et al. (2015).

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Warming Arctic to break down barriers between Atlantic and Pacific fish, study finds

  • 27 Jan 2015, 16:23
  • Robert McSweeney

Fishing off Greenland | Shutterstock

For millions of years, fish species in the Pacific and Atlantic oceans have stuck resolutely to where they belong, kept from venturing between oceans by the cold water of the Arctic.

But new research suggests a warming Arctic could soon see fish putting aside their differences and bridging this chilly divide. And this could have implications for native species and commercial fisheries, the researchers say.

A natural barrier

For most of the last 2.6 million years, the cold temperatures and low nutrient levels of the Arctic have deterred fish species from crossing between the Pacific and Atlantic oceans.

The cold conditions mean at present only 135 of more than 800 known fish species are found in latitudes north of where the UK sits, in either the Atlantic or Pacific Ocean.

But a new study, published in Nature Climate Change, finds that with Arctic temperatures increasing almost twice as fast as the global average, this natural barrier is set to weaken.

Melting sea ice will mean ocean currents can carry warmer water and nutrients into Arctic water, taking fish further north and potentially allowing them to mix between oceans.

'Rapid explosion in fish biodiversity'

The researchers use computer models to forecast future ocean conditions such as surface temperatures, salinity, and currents, and project how the distribution of different fish species could respond to climate change.

They analysed how suitable the Arctic seas would be for over 500 fish species during this century if greenhouse gas emissions continue at current rates.

The maps below show that many species will gradually progress north, eventually reaching the northern coasts of Canada and Russia, where fish from each ocean can mix. Their modelling shows that by 2100, 44 species could enter the Atlantic from the Pacific, with 41 species potentially crossing back the other way.

Wisz Et Al . (2015) Fig 1 Fish Interchange

Projected number of fish species in high latitudes under business-as-usual greenhouse gas emissions. Results shown for 2015, 2050 and 2100. The dark blue show areas with the most species present. Source: Wisz et al. (2015).

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Expect twice as many extreme La Niña events under climate change, study warns

  • 26 Jan 2015, 16:00
  • Robert McSweeney

2011 La Nina in Bangkok | Shutterstock

The Pacific weather phenomenon known as El Niño or 'The Little Boy' is regularly in the news. Scientists keep a close eye on its status as events can cause devastating extreme weather around the world.

But El Niño has a lesser-known sister, La Niña, which also has a dramatic impact on global weather. Now a new study suggests that we could see La Niña events occurring twice as often as the climate warms.

The lesser-known sibling

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

La Niña, or 'The Little Girl', is El Niño's cold water counterpart. During La Niña events the trade winds strengthen, and the central and eastern Pacific Ocean becomes even colder than normal. La Niñas are known to bring drought to the southwestern US, floods to Central America, and hurricanes to the Atlantic Ocean.

Together, the warm and cold events form the El Niño-Southern Oscillation (ENSO), and cause most of the fluctuations in global weather we see from one year to the next.

Understanding how extreme La Niña will change as global temperatures rise has challenged scientists for the past three decades. A new paper, published in Nature Climate Change, suggests that extreme La Niña events will occur almost twice as often in the twenty-first century than they did in the twentieth.

La -nina

Credit: Rosamund Pearce, Carbon Brief

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DNA: How it's helping scientists understand species’ adaptation to climate change

  • 21 Jan 2015, 17:00
  • Robert McSweeney

DNA molecules | Shutterstock

How species respond to climate change could well determine their chances of survival. A new paper describes how scientists are finding new ways to understand how plants and creatures adapt to climate change - by digging deep into their DNA.

The methods are allowing scientists to measure responses to climate change at a greater scale than ever before, the study's lead author tells Carbon Brief.

DNA sequencing

DNA holds all the genetic information that controls how an organism will develop and function. In humans, it dictates physical traits such as height and  eye colour.

DNA sequencing is the way scientists identify which genes control particular traits in a species. But as organisms may have millions or billions of pieces of DNA, sequencing can be a lengthy process.

The new paper, published in BioScience journal, describes how a technology called 'next-generation DNA sequencing' (NGS) allows scientists to analyse millions of pieces of DNA at the same time. This dramatically reduces how much time and money sequencing takes, the paper says.

Lead author, Prof Jonathon Stillman, uses an analogy of analysing a haystack to describe NGS. Using traditional methods you would need to pick out a few straws and use those to try understand the whole haystack, he says, but with NGS you can look at every straw of hay individually.

Move, adapt or die

So what are scientists doing with all this genetic information?

There are three ways a species can respond to changing conditions: move, adapt or die. While it is relatively easy to measure if a species is dying out, monitoring how it moves or adapts is more difficult. This is because scientists need to be able to study how its DNA or physical characteristics are changing.

Scientists use the data they gather from NGS to see where species migrate and which physical traits they're developing to survive. One  study, for example, uses NGS to track how the habitat of three species of giant clams expanded as sea levels rose after the last ice age. And a  study also published this week shows how polar bears have gradually migrated north in search of more year-round sea ice.

There's more than one way that a species can adapt, the study says, and NGS can help with both.

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How the Met Office forecast a hot 2014 and why it thinks 2015 may be even hotter

  • 21 Jan 2015, 14:30
  • Simon Evans

When the Met Office publishes its 2014 global temperature figure on Monday, a group of scientists will be quietly congratulating themselves for having correctly forecast the outcome.

Just over a year ago in December 2013 the Met Office forecast that 2014's temperature would be 0.57 degrees Celsius above the long-term average, a statistical tie for the warmest year on record. Its forecast looks set to be right on the money, agreeing with actual temperatures to within a few hundredths of a degree.

The Met Office has been predicting global temperatures one year in advance since 1999, and it turns out its scientists are rather good at this.

Carbon Brief spoke to the Met Office's Professor Chris Folland to find out how his team forecast the hot year for 2014 and why they are forecasting that 2015 could be even hotter.

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Melting glaciers set to release more organic carbon as temperatures climb

  • 19 Jan 2015, 17:00
  • Robert McSweeney

Melting glacier | Shutterstock

Melting ice may affect more than sea levels, according to new research. As the earth warms, more of the carbon locked up in glaciers and ice sheets will be released into surrounding rivers and oceans.

This means that, as well as pushing up sea levels, melting ice could have unknown impacts on marine life.

Carbon release to increase by half

Glaciers and ice sheets cover around 11 per cent of Earth's land surface and hold around 70 per cent of its freshwater. These giant stores of ice also hold  organic carbon. Carbon accumulates in new snow and ice, and is released as the glacier melts.

A new study, published today in Nature Geoscience, finds the release of this carbon will speed up as the Earth warms due to climate change.

Around 15 million tonnes of extra organic carbon will be lost from melting glaciers over the next 35 years in the form of tiny dissolved particles, the researchers say. Ice also contains larger 'particulate' carbon, which are like bits of sediment that a river carries.

This extra organic carbon is 47 per cent more than we could expect without climate change, and equivalent to around half of what the Amazon river carries each year, the researchers say. 

Organic carbon provides food for tiny organisms at the bottom of the food web. So the extra carbon flowing into rivers and oceans may affect the plants and animals that live around the ice sheets, the researchers say. Adding organic carbon can also affect the chemistry of water, by making it more acidic, for example.

A research first

The research is the first to estimate the total amount of organic carbon held in ice across the world. Researchers collected measurements of organic carbon concentrations from more than 300 samples of glacier and ice sheets in four continents, as the map below shows.  

Hood Et Al (2015) Fig 1 Glacier DOC

Scientists collected organic carbon samples across four continents. Photos show examples of a) Alaska, b) Tibet, c) Dry Valley glaciers in Antarctica, and d) the Greenland Ice Sheet. Source: Hood et al. (2015)

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