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Category — Sea Level Rise

NOAA’s satellites are on the chopping block. Here’s why we need them.

Our eyes in the sky are facing budget cuts On Friday, The Washington Post reportedly obtained a memo from within the Trump administration about proposed funding for National Oceanic and Atmospheric Administration (NOAA). The memo outlined steep cuts to several divisions, including the elimination of the $73 million Sea Grant research program, cuts to climate research… [Read more →]

March 7, 2017   No Comments

Dark shadow falls on melting icecap

Tim Radford

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Signs of melting can be seen as darkness descends on the Greenland icecap. Image: Matthew Hoffmann/NASA ICE via Wikimedia Commons

Dust blowing in from warming areas of the Arctic is causing the Greenland icecap to melt faster by reducing the whiteness that reflects light and keeps it cool 

French scientists have identified a new mechanism that could cause the Greenland icecap to melt even faster – because dust is making its surface darker.

Marie Dumont, of the French national meteorological service, Météo-France, reports with colleagues in Nature Geoscience that, since 2009, the snows of the Arctic region’s biggest single permanent white space have been steadily darkened by “light-absorbing impurities” − known to the rest of the world simply as dust.

The Arctic has always been cold and white, simply because it is not just cold but is also white. The phenomenon is called albedo. Regions with a high albedo reflect light and stay cooler, so ice is a form of self-insulation.

Conversely, things that absorb light become warmer − and satellite data analysed by Dr Dumont and her fellow researchers shows that the Greenland ice is getting darker in the springtime.

They think the dust is blowing in from areas of the Arctic that are losing snow cover much earlier in the season as the climate warms. And, they calculate, this steady darkening alone has led to “significant” melting of the icecap.

This finding is ominous. What the researchers have identified is yet another case of what engineers call positive feedback. In the last 30 years, the Arctic sea ice has been in retreat, and researchers expect that, later in the century, the Arctic ocean will be entirely free of ice most summers. [Read more →]

June 13, 2014   No Comments

No way back for West Antarctic glaciers

Tim Radford

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Birth of an iceberg: a massive crack in West Antarctica’s Pine Island glacier. Image: Nasa Earth Observatory via Wikimedia Commons

Satellite data analysis reveals the ominous news that the melting glaciers of West Antarctica have passed the ‘point of no return’ as the southern hemisphere gets warmer

The glaciers of the West Antarctic may be in irreversible retreat, according to the evidence of satellite data analysed by scientists at the US space agency Nasa.

The study of 19 years of data, due to be reported in the journal Geophysical Research Letters, confirms the ominous news that the southern hemisphere is not just warming − it is that it is warming in a way that speeds up the melting of the West Antarctic glaciers.

Long ago, glaciologists began to wonder whether the West Antarctic ice sheet was inherently unstable. The water locked in the ice sheet in the Amundsen Sea region – the area the Nasa researchers examined − is enough to raise global sea levels by more than a metre. If the whole West Antarctic ice sheet turned to water, sea levels would rise by at least five metres. [Read more →]

May 26, 2014   No Comments

Greenland ice may melt even faster

 Tim Radford

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Melting away: an aerial view of the margin of Greenland’s threatened ice sheet. Image: Hannes Grobe/Alfred Wegener Institute via Wikimedia Commons

Research scientists discover that the vulnerability of Greenland’s glaciers to global warming is much greater than feared, increasing the threat of rising sea levels around the globe 

Just days after US researchers identified geophysical reasons why West Antarctica’s glaciers are increasingly vulnerable to global warming, a partner team has pinpointed a related cause for alarm in Greenland.

Many of the bedrock crevices and canyons down which the island’s glaciers flow have basements that are below sea level. This means that as warm Atlantic waters hit the glacier fronts, the glaciers themselves become more vulnerable to global warming and increasingly likely to melt at a faster rate.

Researchers have been worried for years about rates of melting in Greenland, which is why scientific attention to the vast, ancient ice cap has been stepped up. But the latest finding suggests that what had seemed bad news could turn out to be much, much worse.

If accelerated melting does happen – and all such predictions will be tested initially by yet more research, and then ultimately by time itself – it will be the consequence of an unholy mix of man-made global warming and entirely accidental geomorphology.

The presumption is that terrestrial landforms are routinely above the sea’s highest tides. But Mathieu Morlighem, of the University of California, Irvine, and colleagues – one of whom is Eric Rignot, who authored the research on West Antarctic glaciers, reported in Nature Geoscience − found that this is not always the case. [Read more →]

May 26, 2014   No Comments

Rising sea levels threaten Los Angeles

 Tim Radford

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Residents of the Cabrillo Marine Aquarium, one of the Los Angeles buildings at risk from sea level rise. Image: By Jllm06 via Wikimedia Commons

As much of California and the western US endures a severe drought, the city of Los Angeles is at increasing risk from rising sea levels, researchers say.

Los Angeles, City of the Angels in southern California, sits on a flat shelf of the Pacific coast of America, with a view of the sea. And if climate scientists are right, it could soon have an even closer view of the sea.

The city of more than 12 million people occupies 12,000 square kilometres of land, much of it no more than three metres above sea level. By 2050, rising sea levels could pose a threat to the infrastructure, museums and historic buildings of this great capital of entertainment, education, business, tourism and international trade, according to a new study by the University of Southern California.

“Some low-lying areas within the city’s jurisdiction, such as Venice Beach and some areas of Wilmington and San Pedro, are already vulnerable to flooding”, says Phyllis Grifman, lead author of the report, commissioned by the city and the USC Sea Grant Program.

“Identifying where flooding is already observed during periods of storms and high tides, and analyzing other areas where flooding is projected, are key elements to effective planning for the future.”

The city has already started to prepare for climate change: in June last year it published a report from the University of California Los Angeles on the pattern of snow fall and spring melt over recent decades and the ominous message for winter sports and summer water levels. [Read more →]

February 23, 2014   No Comments

Warsaw – Day 3: World faces more ‘perfect storms’

Paul Brown in Warsaw

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Angola’s national tree, the imbondeiro or baobab, helped it through the 2013 drought. Image: Alfred Weidinger via Wikimedia Commons

One of the Climate News Network editors, Paul Brown, is in the Polish capital, host of the UN climate talks – the 19th Conference of the Parties (COP 19) of the United Nations Framework Convention on Climate Change. His latest report describes records continuing to tumble as sea levels rise and warming continues in 2013.

The world continues to heat up in 2013, with regional temperature records being broken and sea level rise accelerating, the World Meteorological Organisation (WMO) says in its latest report, Provisional Statement on Status of Climate in 2013.

Sea level rise was particularly significant in the Pacific around the Philippines and had contributed greatly to the devastation caused by the super-typhoon Haiyan, Jerry Lengoasa, deputy general secretary general of the WMO, said here.

The population should have been warned about the tsunami effect of a seven-metre storm surge caused by the typhoon, he said, so that they could have been better prepared to retreat to higher ground.

With the typhoon season not over yet there had already been 30 named storms in the Pacific this year; this was above the average of the last three decades.

Mr Lengoasa said: “What the science tells us is not that there will be more storms, but that the storms we do have will be more violent. ‘Perfect storms’, if we can call them that, like hurricane Sandy last year and typhoon Haiyan this year will become the normal.”

Sea level had risen a third of a metre in the central Philippine area since 1901, making the area much more vulnerable to storm surges. The average sea level rise round the globe was much lower but was speeding up, and was now 3.2 millimetres a year. This is double the annual average of the last century – 1.6 mm. [Read more →]

November 13, 2013   No Comments

Warming oceans will affect the poorest

Tim Radford

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Livelihoods like this Ghanaian fisherman’s are threatened by warming oceans. Image: Steve Evans via Wikimedia Commons

By 2100, the world’s oceans will be warmer and more acidic, with less dissolved oxygen and lower yields of fish and shellfish. And that will make life very difficult for up to 870 million of the world’s poorest people who rely on the sea for food, jobs and income.

Camilo Mora of the University of Hawaii and colleagues report in the journal Public Library of Science Biology that greenhouse gas emissions from industry and power generation have begun to trigger biogeochemical changes in the oceans that will impose huge costs.

These changes are likely to cascade through marine ecosystems and habitats to the deep ocean itself, and to affect humans along the way.

“The consequence of these co-occurring changes are massive – everything from species survival, to abundance, to range size, to body size, to species richness, to ecosystem functioning are affected by changes in ocean biogeochemistry,” said Dr Mora.

Mora and fellow oceanographers made headlines earlier this month by calculating the year in which any location on Earth was likely to experience dramatic and inexorable climate change: the researchers arrived at a mean date of 2047 (give or take six years on either side) for change, with the first impact in West Papuaby 2020.

The PLOS Biology paperonce again tries to take a global view of change on the blue planet. The researchers calculated the effect of two scenarios for the future: one in which the world rapidly tries to reduce emissions, and the notorious business-as-usual scenario, which will take carbon dioxide concentrations to the unprecedented level of 900 parts per million by 2100. [Read more →]

October 25, 2013   No Comments

The IPCC’s Fifth Assessment Report

Climate News Network Editors

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Spegelsalen glacier in Norway: Humans are the dominant cause of recent warming, the IPCC says. Image: Richard Strimbeck via Wikimedia Commons

Summary for Policymakers of the Working Group I contribution to the Fifth Assessment Report

A note from the Climate News Network editors: we have prepared this very abbreviated version of the first instalment of the IPCC’s Fifth Assessment Report (AR5) to serve as an objective guide to some of the headline issues it covers. It is in no sense an evaluation of what the Summary says: the wording is that of the IPCC authors themselves, except for a few cases where we have added headings. The AR5 uses a different basis as input to models from that used in its 2007 predecessor, AR4: instead of emissions scenarios, it speaks of RCPs, representative concentration pathways. So it is not possible everywhere to make a direct comparison between AR4 and AR5, though the text does so in some cases, and at the end we provide a very short list of the two reports’ conclusions on several key issues. The language of science can be complex. What follows is the IPCC scientists’ language. In the following days and weeks we will be reporting in more detail on some of their findings.

In this Summary for Policymakers, the following summary terms are used to describe the available evidence: limited, medium, or robust; and for the degree of agreement: low, medium, or high. A level of confidence is expressed using five qualifiers: very low, low, medium, high, and very high, and typeset in italics, e.g., medium confidence. For a given evidence and agreement statement, different confidence levels can be assigned, but increasing levels of evidence and degrees of agreement are correlated with increasing confidence. In this Summary the following terms have been used to indicate the assessed likelihood of an outcome or a result: virtually certain 99–100% probability, very likely 90–100%, likely 66–100%, about as likely as not 33–66%, unlikely 0–33%, very unlikely 0–10%, exceptionally unlikely 0–1%. Additional terms (extremely likely: 95–100%, more likely than not >50–100%, and extremely unlikely 0–5%) may also be used when appropriate.

Observed Changes in the Climate System

Atmosphere

Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased

Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850.

For the longest period when calculation of regional trends is sufficiently complete (1901–2012), almost the entire globe has experienced surface warming.

In addition to robust multi-decadal warming, global mean surface temperature exhibits substantial decadal and interannual variability. Due to natural variability, trends based on short records are very sensitive to the beginning and end dates and do not in general reflect long-term climate trends.

As one example, the rate of warming over the past 15 years, which begins with a strong El Niño, is smaller than the rate calculated since 1951.

Changes in many extreme weather and climate events have been observed since about 1950. It is very likely that the number of cold days and nights has decreased and the number of warm days and nights has increased on the global scale [Read more →]

September 27, 2013   No Comments