Analysis

This year's Arctic sea ice minimum is sixth lowest on record

  • 22 Sep 2014, 17:39
  • Robert McSweeney

The eight lowest measurements of Arctic summer sea-ice extent occurred in the last eight years, scientists confirmed today.

The findings were presented by Professor Julienne Stroeve from the National Snow & Ice Data Centre (NSIDC) at a Royal Society conference on Arctic sea ice reduction.

On the 17th September satellites recorded the Arctic summer minimum extent at 5.01 million square kilometers (sq km). Stroeve confirmed that this year's summer sea-ice extent is the sixth lowest on record, in a series of satellite measurments stretching back over thirty years.

Arctic sea ice - conditions in context.

Sea-ice minimum

Mid to late September marks the end of the Arctic summer, and the point when Arctic ice is at it's smallest extent, before it freezes up again as temperatures fall in the autumn.

Measurements of sea ice taken over the past decades suggest the rate of sea-ice loss is accelerating.

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Climate snails study shows peer review continues to function as expected

  • 22 Sep 2014, 15:10
  • Roz Pidcock

Something is amiss in the world of scientific publishing, claimed The Times this weekend. And not for the first time. This is the latest in a  series  of articles suggesting research downplaying the seriousness of climate change impacts is being suppressed by top scientific journals.

Last time, scientists dismissed the Times' story as a case of peer review in action. It's difficult to see what the difference is this time.

"False alarm"

Seven years ago, a conservation scientist in the Seychelles published a paper in one of the Royal Society's journals, Biological Letters. It concluded the only known population of a type of snail was now thought to be extinct, after declining rapidly in the late 20th century.

In Saturday's Times article, journalist Ben Webster said:

"[The research] was presented as shocking evidence of the damage being done by climate change: a species driven to extinction because of a decline in rainfall in its only habitat."

In its recent report, the Intergovernmental Panel on Climate Change (IPCC) warned the fast pace of climate change could have consequences for many species. It concluded:

"A large fraction of both terrestrial and freshwater species faces increased extinction risk under projected climate change during and beyond the 21st century."

Well, the snail has apparently been rediscovered on a remote island. The Times suggests this "prompts questions" over the Royal Society "raising false alarm" about climate change.

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How climate-ready is your house?

  • 18 Sep 2014, 17:22
  • Robert McSweeney

Sandbags | Shutterstock

Are you pulling out all the stops to climate-proof your home? Have you installed ceiling fans, planted trees for shade and taken out flood insurance? It's unlikely you have, according to a new study of household actions in the UK.

While we make simple actions to deal with a cold snap or heatwave, the research finds, households are struggling to prepare for long-term changes in climate.

What action can you take?

As global leaders prepare to convene in New York to discuss how to curb greenhouse gas emissions, a new paper discusses another side to limiting climate change - adaptation.

Adaptation means taking steps to increase our resilience against climate change that our past emissions have already committed us to, impacts that are now unavoidable.

The study, published in the journal Climatic Change, looks at adaptation measures people can take in their own homes. And the good news, is some actions are easy.  You've probably done many without realising. Putting on an extra jumper in a cold spell or eschewing the Sunday roast in favour of a salad during a heatwave are both adaptive responses.

Some actions aren't as simple as changing your diet or dipping into your wardrobe, however.

The study looks reviews published research on climate adaptation in UK households and finds that while we're pretty good at doing the easy things, we're not so great at making plans for the long-term.

A checklist

The paper runs through some adaptation options available to UK households, which we've illustrated in a checklist below. The list on the left are examples of actions for managing current risks, while the list on the right shows how to climate-proof for the longer-term.

 

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An uncertain future for global farming under climate change, study shows

  • 17 Sep 2014, 20:01
  • Robert McSweeney

Maize Plants | Shutterstock

Climate change is likely to cause an expansion of land suitable for growing crops globally, but on average the quality of land will decline, a new study shows.

A warmer world would mean more cropland for northern latitude countries such as China, Russia and Canada, but there are trade-offs elsewhere, with much of Africa having to manage with less cropland and fewer harvests per year.

Suitable cropland

Not everywhere in the world is suitable for growing crops. Some areas are too dry, or too cold, while other areas have poor quality soil or are too hilly. The climate plays a significant role in determining what we can grow and where.

At the moment, about 40 per cent of the Earth's land is used for farming, though there are huge differences between countries. For example, over 60 per cent of India is used for agriculture, whereas the figure for Canada is much lower, at just seven per cent.

You can see in the map below how this varies across the world; the darker the red colour, the more land is used for farming.

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25 inspirational texts about climate change

  • 15 Sep 2014, 16:15
  • Simon Evans

Around this time each September, thousands of students will go off to study climate change at university. But sometimes climate and environmental issues can be pretty dry.

So we asked 25 thinkers, writers and journalists a simple question: What books or readings inspired you to get involved in climate change-related work?

We were expecting to get back a list of books - and we did. But we also got some interesting insights into why people work on this issue, why they started, and why they carry on.

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Factcheck: Telegraph wrongly accuses BBC of “blatantly untrue” climate reporting

  • 15 Sep 2014, 15:25
  • Roz Pidcock

In yesterday's Telegraph, climate skeptic commentator Christopher Booker argues a recent BBC News piece makes claims about rising carbon dioxide that are "blatantly untrue".

He also accuses the broadcaster of repeating theories about ocean warming that scientists have "ridiculed as make-believe". But a quick look shows his accusations don't stand up.

Carbon rising

In an article  criticising the broadcaster for its climate science coverage, Booker cites a BBC radio news article on a recent World Meteorological Organisation (WMO) report.

The report looked in detail at carbon dioxide levels in the atmosphere, and how they're changing. It found greenhouse gases reached a record high of 396 parts per million (ppm) in 2013 - that's 42 per cent higher than pre-industrial levels.

Global carbon dioxide concentrations rose by nearly 3 ppm from 2012 to 2013 - the largest annual increase since 1984, the report also found.

WMO_CO2_growth

Global growth in atmospheric carbon dioxide from 1984 to 2013 (shaded columns are annual averages). Source: WMO annual Greenhouse Gas Bulletin for 2013

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Asian monsoon discovery suggests rains will increase under climate change

  • 14 Sep 2014, 19:19
  • Robert McSweeney

India Flash Flood | Shutterstock

Asian monsoon rains will intensify as carbon dioxide levels and temperatures increase. That's the prediction made by a new study, that also discovers the monsoon system has existed for at least 15 million years longer than previously thought.

Intense rainfall

The monsoon is the largest climate system in the world. It brings intense rainfall to much of mainland Asia and is the lifeblood of agriculture-reliant economies in the region. It can also bring devastating floods, as seen in  Kashmir this week.

The research, published in Nature, found that the strength of monsoon rains has varied over the past 40 million years as the amount of carbon dioxide in the atmosphere has changed naturally.

The monsoon system emerged at a time when levels of carbon dioxide levels were three or four times what they are today, the researchers say. It then weakened as carbon dioxide levels gradually reduced and the Earth entered an ice age 34 million years ago.

The study reinforces what scientists already know - that there's a connection between the strength of the greenhouse effect and the Asian monsoon system. But as Dr Alexis Licht, lead author on the paper, tells us:

"This suggests that the monsoons may be more sensitive to global climate change than we thought."

The latest IPCC projections suggest an increase in both average and extreme rainfall in south Asia (see figure below) in all scenarios of future emissions. According to Licht, their research "supports the last IPCC report, predicting intensified monsoonal precipitation in Asia."

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Rising air temperatures caused Antarctic ice shelf collapse

  • 11 Sep 2014, 19:04
  • Robert McSweeney

Larsen-B Ice Shelf | Shutterstock

The collapse of a giant ice shelf in Antarctica in 2002 was the result of warmer air temperatures new research concludes, allowing scientists to identify two clear ways in which ice shelves become unstable.

Single summer

At the beginning of February 2002, the Larsen-B ice shelf stretched across 3,250 square kilometers, an area larger than Luxemburg. By the end of the following month it was gone.

In the space of a single Antarctic summer the entire 220-metre thick ice shelf disintegrated into the sea.

Since the dramatic collapse, scientists have been trying to understand how the shelf could disappear so quickly.

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Greenhouse gas concentrations hit record high

  • 09 Sep 2014, 16:23
  • Robert McSweeney

Mauna Loa | Shutterstock

Greenhouse gas levels in the atmosphere reached a record high in 2013, according to the latest measurements by the World Meteorological Organisation.

As announced in their annual Greenhouse Gas Bulletin, the amount of carbon dioxide in the atmosphere has reached 396 parts per million (ppm) - 42 per cent higher than pre-industrial levels.

Largest increase

The World Meteorological Organisation's (WMO) measurements revealed an increase in global carbon dioxide concentrations from 2012 to 2013 of almost 3 ppm. This is larger than recent annual increases of around 2.1 ppm and the largest annual increase since 1984.

The steady increase in annual carbon dioxide over the past 30 years is shown in the upper graph below. These increases are primarily caused by burning fossil fuels such as oil, coal and gas, but cement production, deforestation and land use change also contribute.

The lower graph shows how the annual increase, or growth rate, has varied over the same period. It shows the peak in 2013 and also an earlier spike in growth rate in 1998, which was the result of widespread wildfires during a strong El Niño event.

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Scientists may have solved a climate change mystery using Greenland ice cores

  • 04 Sep 2014, 19:09
  • Robert McSweeney

Greenland Camp | Oregon State Uni

Scientists have long known that carbon dioxide is the main cause of most of the warming we've seen since pre-industrial times. But there are periods in the Earth's distant past when the connection between carbon dioxide and temperature rise has been harder to see.

New research into Greenland's ice sheets now seems to have explained one of the mysteries of our climatic past, confirming the importance of carbon dioxide on global temperature changes.

Mystery interval

Around 20,000 years ago the Earth was emerging from an ice age as orbital changes meant it received slightly more of the sun's energy.

As ice sheets melted into the oceans, sea levels rose and ocean circulation patterns changed.

Scientists think these changes caused carbon dioxide from the oceans to be released into the atmosphere.

Yet despite the planet being closer to the sun and higher levels of carbon dioxide, records for Greenland didn't seem to show much change in temperature. While the rest of the northern hemisphere appeared to warm, Greenland didn't seem to follow suit for another 3,000 years. Scientists couldn't explain why, and it was even dubbed the 'mystery interval' by one study.

But now the new study published in the journal Science suggests that temperatures actually had risen - but the rise wasn't captured by earlier ice core records.

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