Tag Archives: climate change

Finally! The Greenland deglaciation paradox sorted.

from ScienceDaily

Bo Vinther prepares an ice core for visual inspection. Credit: Photograph by Christian Morel

A new study of three ice cores from Greenland documents the warming of the large ice sheet at the end of the last ice age — resolving a long-standing paradox over when that warming occurred.

 Large ice sheets covered North America and northern Europe some 20,000 years ago during the coldest part of the ice age, when global average temperatures were about four degrees Celsius (or seven degrees Fahrenheit) colder than during pre-industrial times. And then changes in Earth’s orbit around the sun increased the solar energy reaching Greenland. Beginning some 18,000 years ago, release of carbon from the deep ocean led to a graduate rise in atmospheric carbon dioxide (CO2).

Yet past analysis of ice cores from Greenland did not show any warming response as would be expected from an increase in CO2 and solar energy flux, the researchers note.

In this new study, funded by the National Science Foundation and published this week in the journal Science, scientists reconstructed air temperatures by examining ratios of nitrogen isotopes in air trapped within the ice instead of isotopes in the ice itself, which had been used in past studies.

Not only did the new analysis detect significant warming in response to increasing atmospheric CO2, it documents a warming trend at a rate closely matching what climate change models predict should have happened as Earth shifted out of its ice age, according to lead author Christo Buizert, a postdoctoral researcher at Oregon State University and lead author on the Science article.

“The Greenland isotope records from the ice itself suggest that temperatures 12,000 years ago during the so-called Younger Dryas period near the end of the ice age were virtually the same in Greenland as they were 18,000 years ago when much of the northern hemisphere was still covered in ice,” Buizert said. “That never made much sense because between 18,000 and 12,000 years ago atmospheric CO2 levels rose quite a bit.”

“But when you reconstruct the temperature history using nitrogen isotope ratios as a proxy for temperature, you get a much different picture,” Buizert pointed out. “The nitrogen-based temperature record shows that by 12,000 years ago, Greenland temperatures had already warmed by about five degrees (Celsius), very close to what climate models predict should have happened, given the conditions.”

Reconstructing temperatures by using water isotopes provides useful information about when temperatures shift but can be difficult to calibrate because of changes in the water cycle, according to Edward Brook, an Oregon State paleoclimatologist and co-author on the Science study.

“The water isotopes are delivered in Greenland through snowfall and during an ice age, snowfall patterns change,” Brook noted. “It may be that the presence of the giant ice sheet made snow more likely to fall in the summer instead of winter, which can account for the warmer-than-expected temperatures because the snow records the temperature at the time it fell.”

In addition to the gradual warming of five degrees (C) over a 6,000-year period beginning 18,000 years ago the study investigated two periods of abrupt warming and one period of abrupt cooling documented in the new ice cores. The researchers say their leading hypothesis is that all three episodes are tied to changes in the Atlantic meridional overturning circulation (AMOC), which brings warm water from the tropics into the high northern latitudes.

The first episode caused a jump in Greenland’s air temperatures of 10-15 degrees (C) in just a few decades beginning about 14,700 years ago. An apparent shutdown of the AMOC about 12,800 years ago caused an abrupt cooling of some 5-9 degrees (C), also over a matter of decades.

When the AMOC was reinvigorated again about 11,600 years ago, it caused a jump in temperatures of 8-, 11 degrees (C), which heralded the end of the ice age and the beginning of the climatically warm and stable Holocene period, which allowed human civilization to develop.

“For these extremely abrupt transitions, our data show a clear fingerprint of AMOC variations, which had not yet been established in the ice core studies,” noted Buizert, who is in OSU’s College of Earth, Ocean, and Atmospheric Sciences. “Other evidence for AMOC changes exists in the marine sediment record and our work confirms those findings.”

In their study, the scientists examined three ice cores from Greenland and looked at the gases trapped inside the ice for changes in the isotopic ration of nitrogen, which is very sensitive to temperature change. They found that temperatures in northwest Greenland did not change nearly as much as those in southeastern Greenland — closest to the North Atlantic — clearly suggesting the influence of the AMOC.

“The last deglaciation is a natural example of global warming and climate change,” Buizert said. “It is very important to study this period because it can help us better understand the climate system and how sensitive the surface temperature is to atmospheric CO2.”

“The warming that we observed in Greenland at the end of the ice age had already been predicted correctly by climate models several years ago,” Buizert added. “This gives us more confidence that these models also predict future temperatures correctly.”

 

From Science

Greenland deglaciation puzzles

Louise Claire Sime, British Antarctic Survey, High Cross, Cambridge, CB23 7PP, UK.

About 23,000 years ago, the southern margins of the great Northern Hemisphere ice sheets across Europe and North America began to melt. The melt rate accelerated ∼20,000 years ago, and global sea level eventually rose by ∼130 m as meltwater flowed into the oceans. Ice cores from the Greenland and Antarctic ice sheets show the rise in atmospheric CO2 concentrations that accompanied this shift in global ice volume and climate. However, discrepancies in the temperature reconstructions from these cores have raised questions about the long-term relationship between atmospheric CO2 concentrations and Arctic temperature. On page 1177 of this issue, Buizert et al. (1) report temperature reconstructions from three locations on the Greenland ice sheet that directly address these problems.

Abstract

Greenland ice core water isotopic composition (δ18O) provides detailed evidence for abrupt climate changes but is by itself insufficient for quantitative reconstruction of past temperatures and their spatial patterns. We investigate Greenland temperature evolution during the last deglaciation using independent reconstructions from three ice cores and simulations with a coupled ocean-atmosphere climate model. Contrary to the traditional δ18O interpretation, the Younger Dryas period was 4.5° ± 2°C warmer than the Oldest Dryas, due to increased carbon dioxide forcing and summer insolation. The magnitude of abrupt temperature changes is larger in central Greenland (9° to 14°C) than in the northwest (5° to 9°C), fingerprinting a North Atlantic origin. Simulated changes in temperature seasonality closely track changes in the Atlantic overturning strength and support the hypothesis that abrupt climate change is mostly a winter phenomenon.

 

Original Science Daily article here

Science paper here

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The BOM and data manipulation

All the right-wing nut jobs, unable to produce primary scientific data that disproves anthropogenic climate change and global warming, tend to resort to the time-honored but completely dishonorable tradition of attacking the messenger. The usual suspects have been attacking the Bureau of Meteorology because they don’t like the message that the globe is warming and humans are to blame. The BOM, faced with data that has discontinuities due to instrument changes, location changes and encroachment by urbanisation has had to homogenise their data to remove any factors in the temperature series that aren’t either natural or caused by anthropogenic climate change. Sounds pretty reasonable to me. Of course the idiots out there hear about it and automatically assume the BOM scientists are deliberately fudging data to “tell the global warming story”. I can only assume that none of those idiots have even a basic understanding of statistics, because if they did, they would surely leap at the chance to have their statistical take downs published in scientific journals and bathe in the glory of their statistical brilliance made legitimate?

From the Conversation

No, the Bureau of Meteorology is not fiddling its weather data

Australia’s weather records need careful analysis to correct any introduced errors. Photographic Collection from Australia/Wikimedia Commons, CC BY

Over the past week or so, the Bureau of Meteorology has stood accused of fudging its temperature data records to emphasise warming, in a series of articles in The Australian. The accusation hinges on the method that the Bureau uses to remove non-climate-related changes in its weather station data, referred to as “data homogenisation”.

If true, this would be very serious because these data sets underpin major climate research projects, including deducing how much Australia is warming. But it’s not true.

Crunching the numbers

Data homogenisation techniques are used to varying degrees by many national weather agencies and climate researchers around the world. Although the World Meteorological Organization has guidelines for data homogenisation, the methods used vary from country to country, and in some cases no data homogenisation is applied.

Homogenisation can be necessary for a range of reasons: sometimes stations move, instruments or reporting practices change, or surrounding trees or buildings at a site are altered. Changes can be sudden or gradual. These can all introduce artificial “jumps” (in either direction) in the resulting temperature records. If left uncorrected, these artifacts could leave the data appearing to show spurious warming or cooling trends.

There are many methods that can be used to detect these “inhomogeneities”, and there are other methods (although much harder to implement) that can adjust the data to make sure it is consistent through time. The Bureau uses such a technique to create its Australian Climate Observations Reference Network – Surface Air Temperature (ACORN-SAT) data set. These data are then used to monitor climate variability and change in Australia, to provide input for the State of the Climate reports, and for other purposes too.

In a statement about its climate records, the Bureau said:

The Bureau measures temperature at nearly 800 sites across Australia, chiefly for the purpose of weather forecasting. The ACORN-SAT is a subset of this network comprising 112 locations that are used for climate analysis. The ACORN-SAT stations have been chosen to maximise both length of record and network coverage across the continent. For several years, all of this data has been made publicly available on the Bureau’s web site.

Complex methods

Australia has played a leading role in developing this type of complex data-adjustment technique. In 2010, the Bureau’s Blair Trewin wrote a comprehensive article on the types of inhomogeneities that are found in land temperature records. As a result the International Surface Temperature Initiative (ISTI) has set up a working group to compare homogenisation methods.

Some of our own research at the ARC Centre of Excellence for Climate System Science has tried, with the help of international colleagues, to assess the impacts that different choices can make when using these different homogenisation methods. Much of our work focuses on temperature extremes. We have studied the impacts on large-scale extreme temperature data of changing station networks, different statistical techniques, homogenised versus non-homogenised data, and other uncertainties that might arise.

Our data on extreme temperature trends show that the warming trend across the whole of Australia looks bigger when you don’t homogenise the data than when you do. For example, the adjusted data set (the lower image below) shows a cooling trend over parts of northwest Australia, which isn’t seen in the raw data.

Trends in the frequency of hot days over Australia – unadjusted data using all temperature stations that have at least 40 years of record available for Australia from the GHCN-Daily data set.

Click to enlarge
Trends in the frequency of hot days over Australia – adjusted ACORN-SAT data. The period of trend covers 1951-2010 when both datasets have overlapping data. All data used in figures are available from http://www.climdex.org

Click to enlarge

High-quality data

Far from being a fudge to make warming look more severe than it is, most of the Bureau’s data manipulation has in fact had the effect of reducing the apparent extreme temperature trends across Australia. Cherrypicking weather stations where data have been corrected in a warming direction doesn’t mean the overall picture is wrong.

Data homogenisation is not aimed at producing a predetermined outcome, but rather is an essential process in improving weather data by spotting where temperature records need to be corrected, in either direction. If the Bureau didn’t do it, then we and our fellow climatologists wouldn’t use its data because it would be misleading. What we need are data from which spurious warming or cooling trends have been removed, so that we can see the actual trends.

Marshalling all of the data from the Bureau’s weather stations can be a complicated process, which is why it has been subjected to international peer-review. The Bureau has provided the details of how it is done, despite facing accusations that it has not been open enough.

Valid critiques of data homogenisation techniques are most welcome. But as in all areas of science, from medicine to astronomy, there is only one place that criticisms can legitimately be made. Anyone who thinks they have found fault with the Bureau’s methods should document them thoroughly and reproducibly in the peer-reviewed scientific literature. This allows others to test, evaluate, find errors or produce new methods.

This process has been the basis of all scientific advances in the past couple of centuries and has led to profoundly important advances in knowledge. Abandoning peer-reviewed journals in favour of newspaper articles when adjudicating on scientific methods would be profoundly misguided.

 

Original article here

UPDATE: Today the Conversation expanded on the BOM and data article, by giving advice on how to do your own simple calculations to track temperature changes over time using raw unadjusted data. So it shouldn’t be long before these wannabe right right-wing nut jobs start doing their own analyses and bombarding journals with their fantastic findings that show AGW isn’t happening and that its all a giant conspiracy implemented by the Jewish Bankers to bring in socialism masquerading as environmentalism so when the lizard people want to fake another moon landing they will be better able to control the masses with their global chemtrail program.

 

 

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Hunt launches personal attack on head of Australian solar lobby

Is this any way for a government minister to behave? The fact is, Greg Hunt is a AGW denier like the rest of his lunatic fringe party. He says he accepts the science underpinning climate change but then flags and implements policies that don’t reflect the science. He is either a fraud, completely incompetent or stupid…..or all three.

Hunt launches personal attack on head of Australian solar lobby.

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Ignorance is crippling Australia

and its wilful ignorance at that

Ignorance is crippling Australia.

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Campbell “coal mining” Newman – corrupt.

unicameral

So, how does Queensland Premier Campbell Newman repay the miners who donate to his party? By creating legislation that gives them unfettered access to coal deposits with no community consultation. That’s how. If this isn’t corruption I don’t know what is….

from Queensland Country Life

Legislation definition prompts warnings

COMMUNITY groups are set to lose the right to object to an overwhelming majority of mining projects if a new bill is approved in state parliament, according to Environmental Defenders Office principal solicitor Jo-Anne Bragg.

Passage of the Mineral and Energy Resources (Common Provisions) Bill 2014 will mean 90 per cent of proposed projects would not be open for community comment or objection.

There would also be no public notification of small-scale projects.

The bill is currently in its consultation phase and submissions to the Agriculture, Resources and Environment Committee closed on July 9.

The committee is now considering those submissions before making recommendations that will be considered and debated in parliament.

Jericho beef producers Bruce and Annette Currie wrote a submission to the committee, raising their concerns about the proposal to limit objection rights to only directly affected landholders.

The definition of a ‘directly affected’ landholder is unclear, they said, and the flow-on effects of mining should be considered.

The couple, who operate 25,000-hectare property Speculation, at Jericho, understand the importance of objection rights and were involved in the Alpha coal case in the Land Court.

“We believe it is extremely important that all sectors of the community can comment, object and have appeal rights to government decisions made on ‘regional interest areas’,” they said.

“Our current situation is that if the mines in our area are given the go ahead our cattle property could potentially have its ground water impacted by coal mining; if this occurs then it will destroy our business.

“It is imperative that individuals and community groups can decide if they wish to appeal a government decision. We need and want a right of appeal.”

A diagram from the Environmental Defenders Office about the potential changes.

The Environmental Defenders Office represents landholders and conservation groups on issues ranging from environmental planning to mining and coal seam gas.

EDO principal solicitor Jo-Anne Bragg said the proposed changes would only benefit mining companies.

“Essentially people’s rights are being stripped away without any justification,” she said.

“Cases like the Alpha coal case show how landholders and community groups alike act responsibly and lead to finding that some projects should not go ahead based on groundwater impacts and uncertainties.”

Natural Resources and Mines Minister Andrew Cripps said the Mineral and Energy Resources (Common Provisions) Bill 2014 was about getting the balance between resource development, landholder rights and environmental protection right.

He said the bill contained a number of key benefits for landowners that didn’t previously exist under the former Labor government.

“For the first time, directly affected landowners will have the right to give or withhold their consent for activities to occur close to their homes or businesses,” Mr Cripps said.

“This will provide a clear ‘line in the sand’, increasing the protection from 100 metres to 200 metres for mineral and coal projects.”

Read the original article here

 

 

 

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The climate change denial industry cops another blow

More and more, the climate change denial industry, and it is an industry, is becoming increasingly marginalised. Big business which is generally all about free market ideology and is usually dismissive of the science underpinning anthropogenic climate change.  Insurance companies however, do recognise the threat of human caused climate change and have started rumbling about a lack of government action. You won’t find too many insurance companies funneling money into right-wing anti-science conservative think-tanks. Now, the world’s largest PR firms are also taking a stand.

From the Guardian

World’s top PR companies rule out working with climate deniers

Ten firms say they will not represent clients that deny man-made climate change or seek to block emisson-reducing regulations.

Some of the world’s top PR companies have for the first time publicly ruled out working with climate change deniers, marking a fundamental shift in the multi-billion dollar industry that has grown up around the issue of global warming.

Public relations firms have played a critical role over the years in framing the debate on climate change and its solutions – as well as the extensive disinformation campaigns launched to block those initiatives.

Read the rest here

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If We Release a Small Fraction of Arctic Carbon, ‘We’re Fucked': Climatologist

from Brian Merchant at Motherboard

This week, scientists made a disturbing discovery in the Arctic Ocean: They saw “vast methane plumes escaping from the seafloor,” as the Stockholm University put it in a release disclosing the observations. The plume of methane—a potent greenhouse gas that traps heat more powerfully than carbon dioxide, the chief driver of climate change—was unsettling to the scientists.

But it was even more unnerving to Dr. Jason Box, a widely published climatologist who had been following the expedition. As I was digging into the new development,…. read the rest here.

 

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