New Research

[knocker]

Robust twenty-first-century projections of El Niño and related precipitation variability

The El Niño–Southern Oscillation (ENSO) drives substantial variability in rainfall^{1, 2, 3}, severe weather^{4, 5}, agricultural production^{3, 6}, ecosystems⁷ and disease⁸ in many parts of the world. Given that further human-forced changes in the Earth’s climate system seem inevitable^{9, 10}, the possibility exists that the character of ENSO and its impacts might change over the coming century. Although this issue has been investigated many times during the past 20 years, there is very little consensus on future changes in ENSO, apart from an expectation that ENSO will continue to be a dominant source of year-to-year variability^{9, 11, 12}. Here we show that there are in fact robust projected changes in the spatial patterns of year-to-year ENSO-driven variability in both surface temperature and precipitation. These changes are evident in the two most recent generations of climate models^{13, 14}, using four different scenarios for CO₂ and other radiatively active gases^{14, 15, 16, 17}. By the mid- to late twenty-first century, the projections include an intensification of both El-Niño-driven drying in the western Pacific Ocean and rainfall increases in the central and eastern equatorial Pacific. Experiments with an Atmospheric General Circulation Model reveal that robust projected changes in precipitation anomalies during El Niño years are primarily determined by a nonlinear response to surface global warming. Uncertain projected changes in the amplitude of ENSO-driven surface temperature variability have only a secondary role. Projected changes in key characteristics of ENSO are consequently much clearer than previously realized.

 

 

http://www.nature.com/nature/journal/vaop/ncurrent/full/nature12580.html

[BornFromTheVoid]

 

NAO implicated as a predictor of Northern Hemisphere mean temperature multidecadal variability

 

 The twentieth century Northern Hemisphere mean surface temperature (NHT) is characterized by a multidecadal warming–cooling–warming pattern followed by a flat trend since about 2000 (recent warming hiatus). Here we demonstrate that the North Atlantic Oscillation (NAO) is implicated as a useful predictor of NHT multidecadal variability. Observational analysis shows that the NAO leads both the detrended NHT and oceanic Atlantic Multidecadal Oscillation (AMO) by 15–20 years. Theoretical analysis illuminates that the NAO precedes NHT multidecadal variability through its delayed effect on the AMO due to the large thermal inertia associated with slow oceanic processes. A NAO-based linear model is therefore established to predict the NHT, which gives an excellent hindcast for NHT in 1971–2011 with the recent flat trend well predicted. NHT in 2012–2027 is predicted to fall slightly over the next decades, due to the recent NAO weakening that temporarily offsets the anthropogenically induced warming.

 

 

 

A pretty interesting paper, predicting cooling for the NH up to 2027.

The full PDF is here http://onlinelibrary.wiley.com/doi/10.1002/2013GL057877/pdf

[knocker]

Global ocean currents explain why Northern Hemisphere is the soggier one

 

A quick glance at a world precipitation map shows that most tropical rain falls in the Northern Hemisphere. The Palmyra Atoll, at 6 degrees north, gets 175 inches of rain a year, while an equal distance on the opposite side of the equator gets only 45 inches.

 

Scientists long believed that this was a quirk of the Earth’s geometry – that the ocean basins tilting diagonally while the planet spins pushed tropical rain bands north of the equator. But a new University of Washington study shows that the pattern arises from ocean currents originating from the poles, thousands of miles away.

 

The findings, published Oct. 20 in Nature Geoscience, explain a fundamental feature of the planet’s climate, and show that icy waters affect seasonal rains that are crucial for growing crops in such places as Africa’s Sahel region and southern India.

 

http://www.washington.edu/news/2013/10/20/global-ocean-currents-explain-why-northern-hemisphere-is-the-soggier-one/

Edited October 20, 2013 by knocker

[knocker]

Can't argue too much with this.

 

Johan Rockström: Protecting the Earth’s systems from catastrophic failure

http://ensia.com/interviews/johan-rockstrom-protecting-the-earths-systems-from-catastrophic-failure/

[knocker]

Risk of Amazon Rainforest Dieback is Higher Than IPCC Projects

AUSTIN, Texas —  A new study suggests the southern portion of the Amazon rainforest is at a much higher risk of dieback due to stronger seasonal drying than projections made by the climate models used in the latest report by the Intergovernmental Panel on Climate Change (IPCC). If severe enough, the loss of rainforest could cause the release of large volumes of the greenhouse gas carbon dioxide into the atmosphere. It could also disrupt plant and animal communities in one of the regions of highest biodiversity in the world.

 

 

http://www.utexas.edu/news/2013/10/21/amazon-rainforest-dieback/

Edited October 22, 2013 by knocker

[Gray-Wolf]

I think the combination of man's forest clearances and two , near back to back, 1 in a hundred year droughts have left sections of the Amazon in 'recovery' mode. Any return of drought could be a push to far leading to wholesale die back of mature forest. The loss of rainforest not only removes a valuable carbon sink but also leads to carbon release as the dead forest rots

[Polar Maritime]

Scientists who braved Somali pirates shed light on Sahara's origins

Climate research vessel that escaped pirates in the Horn of Africa in 2001 may have just turned the tables on the accepted scientific view of how the Sahara became a desert ;

 

http://www.theguardian.com/environment/2013/oct/18/scientists-somali-pirates-sahara-origins

 

What the scientists found was that, far from shifting gradually from wet to dry, the climate in the Horn of Africa changed in perhaps as little as 100 to 200 years, incredibly quickly in geological terms. The reason north Africa warmed up, they believe, was a cyclic change in Earth’s orientation toward the sun (called precession) which caused more sunlight to fall during the Northern Hemisphere's summer. But the precession cycle is slow, taking 23,000 years to complete. So why was the changeover in the Horn of Africa so quick?

“It shows something really surprising,†says deMenocal. “It’s evidence that climate doesn’t respond gradually to gradual forcing. It would be wonderful in global warming if everything just kept pace with the gradual rise in CO2, then we could plan for this, we would know what is going to happen, there would be some predictability in it."

But what researchers like Tierney and deMenocal are increasingly finding is that climate doesn’t change in a linear fashion, but suddenly and seemingly unpredictably. That’s because there are positive feedback mechanisms that start to kick in and speed things up. For example, when the Arctic sea ice melts, as it has increasingly in recent years, the area of dark blue heat-absorbing ocean increases, raising temperatures, melting more ice, which in turn raises temperatures still further in an snowballing process.

Tierney and deMenocal suspect that there were similar positive feedback mechanisms at play in the rapid desertification of the Horn of Africa 5,000 years ago. It could involve what is called the Charney mechanism, which posits that as vegetation begins to thin in an area, it changes the reflectivity of the Earth which heats thing up, dries out more vegetation and leads to the rather abrupt formation of deserts. However, the carbon isotope data collected by the team do not suggest that this was the case. Rather, the authors hypothesize that there was a feedback mechanism involving Indian Ocean sea-surface temperatures, which greatly influence how much rain falls over east Africa.

Whether that is in fact what happened remains to be proven. It’s just one of the mysteries that need to be investigated further, deMenocal told me. The authors are itching to get back to the Gulf of Aden to drill even deeper core samples that would provide critical information on climate conditions during the period millions of years ago when humans first evolved from our hominid predecessors. This could throw light on the early stages of human evolution, which happened just next door in the East African Rift and the Horn of Africa.

Edited October 22, 2013 by Polar Maritime

[Devonian]

Scientists who braved Somali pirates shed light on Sahara's origins

Climate research vessel that escaped pirates in the Horn of Africa in 2001 may have just turned the tables on the accepted scientific view of how the Sahara became a desert ;

 

http://www.theguardian.com/environment/2013/oct/18/scientists-somali-pirates-sahara-origins

Interesting

[knocker]

Unprecedented recent summer warmth in Arctic Canada

 

Abstract

[1] Arctic air temperatures have increased in recent decades, along with documented reductions in sea ice, glacier size, and snowcover. However, the extent to which recent Arctic warming has been anomalous with respect to long-term natural climate variability remains uncertain. Here we use 145 radiocarbon dates on rooted tundra plants revealed by receding cold-based ice caps in the Eastern Canadian Arctic to show that 5000 years of regional summertime cooling has been reversed, with average summer temperatures of the last ~100 years now higher than during any century in more than 44,000 years, including peak warmth of the early Holocene when high latitude summer insolation was 9% greater than present. Reconstructed changes in snow line elevation suggest that summers cooled ~2.7 °C over the past 5000 years, approximately twice the response predicted by CMIP5 climate models. Our results indicate that anthropogenic increases in greenhouse gases have led to unprecedented regional warmth.

 

 

 

 

http://onlinelibrary.wiley.com/doi/10.1002/2013GL057188/abstract

Edited October 23, 2013 by knocker

[knocker]

Reading ancient climate from plankton shells

 

Climate changes from millions of years ago are recorded at daily rate in ancient sea shells, new research shows.

 

http://phys.org/news/2013-10-ancient-climate-plankton-shells.html

Edited October 25, 2013 by knocker

[knocker]

I originally put this in the Greenland thread but on reflection it's probably better here.

 

Long-term data reveal: The deep Greenland Sea is warming faster than the World Ocean

 

Since 1993, oceanographers from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI), have carried out regularly expeditions to the Greenland Sea on board the research ice breaker Polarstern to investigate the changes in this region. The programme has always included extensive temperature and salinity measurements. For the present study, the AWI scientists have combined these long term data set with historical observations dating back to the year 1950. The result of their analysis: In the last thirty years, the water temperature between 2000 metres depth and the sea floor has risen by 0.3 degrees centigrade.

 

‘This sounds like a small number, but we need to see this in relation to the large mass of water that has been warmed’ says the AWI scientist and lead author of the study, Dr. Raquel Somavilla Cabrillo. ‘The amount of heat accumulated within the lowest 1.5 kilometres in the abyssal Greenland Sea would warm the atmosphere above Europe by 4 degrees centigrade.  The Greenland Sea is just a small part of the global ocean. However, the observed increase of 0.3 degrees in the deep Greenland Sea is ten times higher than the temperature increase in the global ocean on average. For this reason, this area and the remaining less studied polar oceans need to be taken into consideration’.........................................................................................................................................

 

To fully understand, how the world’s oceans react to climate change, scientists need to investigate the Arctic Ocean in more detail. ‘Due to its large volume and its thermal inertia the deep ocean is a powerful heat buffer for climate warming. Especially, the polar oceans are scarcely studied. If we want to understand the role of the deep ocean in the climate system, we need to expand the measurements to remote regions like the Arctic,†AWI-scientist Schauer says. For that, she has already planned further Polarstern expeditions. In 2015, Ursula Schauer and her group will go back to the Arctic.

 

http://www.awi.de/en...e098d1c372cc1b4

Edited October 26, 2013 by knocker

[knocker]

Scientists eye longer-term forecasts of US heat waves

 

BOULDER -- Scientists have fingerprinted a distinctive atmospheric wave pattern high above the Northern Hemisphere that can foreshadow the emergence of summertime heat waves in the United States more than two weeks in advance.

 

http://www.sciencecodex.com/scientists_eye_longerterm_forecasts_of_us_heat_waves-121790

Edited October 27, 2013 by knocker

[knocker]

El Nino is becoming more active

 

A new approach to analyzing paleo-climate reconstructions of the El Niño Southern Oscillation (ENSO) phenomenon resolves disagreements and reveals that ENSO activity during the 20th century has been unusually high compared to the past 600 years. The results are published in Climate of the Past by a team of scientists from the University of New South Wales, the University of Hawaii International Pacific Research Center and the NOAA Geophysical Fluid Dynamics Laboratory.

Read more at: http://phys.org/news/2013-10-el-nino.html#jCp

Edited October 28, 2013 by knocker

[knocker]

When could global warming reach 4°C?

The Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) assessed a range of scenarios of future greenhouse-gas emissions without policies to specifically reduce emissions, and concluded that these would lead to an increase in global mean temperatures of between 1.6°C and 6.9°C by the end of the twenty-first century, relative to pre-industrial. While much political attention is focused on the potential for global warming of 2°C relative to pre-industrial, the AR4 projections clearly suggest that much greater levels of warming are possible by the end of the twenty-first century in the absence of mitigation. The centre of the range of AR4-projected global warming was approximately 4°C. The higher end of the projected warming was associated with the higher emissions scenarios and models, which included stronger carbon-cycle feedbacks. The highest emissions scenario considered in the AR4 (scenario A1FI) was not examined with complex general circulation models (GCMs) in the AR4, and similarly the uncertainties in climate–carbon-cycle feedbacks were not included in the main set of GCMs. Consequently, the projections of warming for A1FI and/or with different strengths of carbon-cycle feedbacks are often not included in a wider discussion of the AR4 conclusions. While it is still too early to say whether any particular scenario is being tracked by current emissions, A1FI is considered to be as plausible as other non-mitigation scenarios and cannot be ruled out. (A1FI is a part of the A1 family of scenarios, with ‘FI’ standing for ‘fossil intensive’. This is sometimes erroneously written as A1F1, with number 1 instead of letter I.) This paper presents simulations of climate change with an ensemble of GCMs driven by the A1FI scenario, and also assesses the implications of carbon-cycle feedbacks for the climate-change projections. Using these GCM projections along with simple climate-model projections, including uncertainties in carbon-cycle feedbacks, and also comparing against other model projections from the IPCC, our best estimate is that the A1FI emissions scenario would lead to a warming of 4°C relative to pre-industrial during the 2070s. If carbon-cycle feedbacks are stronger, which appears less likely but still credible, then 4°C warming could be reached by the early 2060s in projections that are consistent with the IPCC’s ‘likely range’.

 

 

http://rsta.royalsocietypublishing.org/content/369/1934/196.full.pdf+html

[knocker]

The Reversibility of Sea Level Rise

During the last century, global climate has been warming, and projections indicate that such a warming is likely to continue over coming decades. Most of the extra heat is stored in the ocean, resulting in thermal expansion of seawater and global mean sea level rise. Previous studies have shown that after CO₂ emissions cease or CO₂ concentration is stabilized, global mean surface air temperature stabilizes or decreases slowly, but sea level continues to rise. Using idealized CO₂ scenario simulations with a hierarchy of models including an AOGCM and a step-response model, the authors show how the evolution of thermal expansion can be interpreted in terms of the climate energy balance and the vertical profile of ocean warming. Whereas surface temperature depends on cumulative CO₂ emissions, sea level rise due to thermal expansion depends on the time profile of emissions. Sea level rise is smaller for later emissions, implying that targets to limit sea level rise would need to refer to the rate of emissions, not only to the time integral. Thermal expansion is in principle reversible, but to halt or reverse it quickly requires the radiative forcing to be reduced substantially, which is possible on centennial time scales only by geoengineering. If it could be done, the results indicate that heat would leave the ocean more readily than it entered, but even if thermal expansion were returned to zero, the geographical pattern of sea level would be altered. Therefore, despite any aggressive CO₂ mitigation, regional sea level change is inevitable.

 

 

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-12-00285.1

[knocker]

I thought this paper quite interesting.

 

The Subterranean War on Science

 

Of course Anthony didn't like it and the nutters started streaming out of the woodwork.

 

http://blog.hotwhopper.com/

Edited November 2, 2013 by knocker

[knocker]

What 'pause'?

 

Global temperature evolution 1979–2010

 

http://iopscience.iop.org/1748-9326/6/4/044022/fulltext/

[Fergus Brown]

Changing the subject (but still more or less on theme); I'd appreciate feedback/opinion/derision on a new(ish) idea I am developing at the moment about the communication of environment issues: http://whogoeswithfergus.blogspot.co.uk/

 

All (literally, all) and any thoughts very much welcomed...

 

[VillagePlank]

Changing the subject (but still more or less on theme); I'd appreciate feedback/opinion/derision on a new(ish) idea I am developing at the moment about the communication of environment issues: http://whogoeswithfergus.blogspot.co.uk/

 

All (literally, all) and any thoughts very much welcomed...

 

 

Sustainability is a buzzword, and is, literally, meaningless, since nothing can ever be sustainable due to entropy derived from the 2nd Law of Thermodynamics [1].

 

It's rather like believing in a religion: you first have to accept that you were sinful, are sinful, and will continue to be sinful - to be not sinful requires that extra step that can never be achieved, and, to avoid damnation you have to worship a god.

 

Sustainability is the same, but in this case we delude ourselves, and what we actually mean, is sustain stuff long enough so, crucially, we don't have to worry about it. Perhaps we should kneel down in front of those who peddle such ridiculous concepts for our infinite salvation.

 

The buzzword aside, I think that what we really mean by sustainable, is less impacts by ourselves on our environment. Of which, I know not of one person who disagrees with that.

 

[1] https://en.wikipedia.org/wiki/Second_law_of_thermodynamics

Edited November 5, 2013 by Sparkicle

[knocker]

The idea of sustainable development was first ;presented by the International Union for the Conservation of Nature (IUCN 1980) in an

interarional forum of the World Conservation Strategy. In essence, the concept of sustainable development invoked present development of available resources withthout compromising the ability of future generations  to meet their needs. Many disagreed with this as being an abstract ideal that is impossible to achieve.

 

Essentially that boils down to what you said, less impacts by ourselves on our environment So we had better leave massive deforestation out.

Edited November 5, 2013 by knocker

[knocker]

The oldest ice core – Finding a 1.5 million-year record of Earth’s climate

 

How far into the past can ice-core records go? Scientists have now identified regions in Antarctica they say could store information about Earth’s climate and greenhouse gases extending as far back as 1.5 million years, almost twice as old as the oldest ice core drilled to date. The results are published today in Climate of the Past, an open access journal of the European Geosciences Union (EGU).

 

http://www.egu.eu/news/77/the-oldest-ice-core-finding-a-15-million-year-record-of-earths-climate/

[Gray-Wolf]

http://physicsworld.com/cws/article/news/2013/nov/05/comprehensive-study-shows-cosmic-rays-are-not-causing-global-warming

 

I'll post this here as well as on the 'sun' thread. Can we finally drop the 'Cosmic Rays' thing now please?

[jonboy]

http://physicsworld.com/cws/article/news/2013/nov/05/comprehensive-study-shows-cosmic-rays-are-not-causing-global-warming

 

I'll post this here as well as on the 'sun' thread. Can we finally drop the 'Cosmic Rays' thing now please?

 

No

"The significance of the findings was that the results were negative – I found little evidence of the cosmic rays having a discernible affect on a range of common meteorological elements: temperature, the barometric pressure or precipitation," says Benestad. "Not for the global mean at least. One possible exception may have been for parts of Europe, however

 

 

Clearly more research needed

[Coast]

 

The levels of gases in the atmosphere that drive global warming increased to a record high in 2012.

 

According to the World Meteorological Organization (WMO), atmospheric CO2 grew more rapidly last year than its average rise over the past decade. Concentrations of methane and nitrous oxide also broke previous records

 

Thanks to carbon dioxide and these other gases, the WMO says the warming effect on our climate has increased by almost a third since 1990. The WMO's annual greenhouse gas bulletin measures concentrations in the atmosphere, not emissions on the ground. Carbon dioxide is the most important of the gases that they track, but only about half of the CO2 that's emitted by human activities remains in the atmosphere, with the rest being absorbed by the plants, trees, the land and the oceans.

 

Since the start of the industrial era in 1750, global average levels of CO2 in the atmosphere have increased by 141%. According to the WMO there were 393.1 parts per million (ppm) of carbon dioxide in the atmosphere in 2012, an increase of 2.2ppm over 2011. This was above the yearly average of 2.02ppm over the past decade.

 

"The observations highlight yet again how heat-trapping gases from human activities have upset the natural balance of our atmosphere and are a major contribution to climate change," said WMO Secretary-General Michel Jarraud. While the daily measurement of carbon dioxide in the atmosphere exceeded the symbolic 400ppm mark in May this year, according to the WMO the global annual average CO2 concentration will cross this point in 2015 or 2016.

 

Levels of methane also reached record highs in 2012 of 1,819 parts per billion. Concentrations have been increasing since 2007 after a period when they appeared to be levelling off. The WMO report says that it is not yet possible to attribute the methane increase to either human activities like cattle breeding and landfills or natural sources such as wetlands.

 

They believe that the rising emissions come from the tropical and mid-latitude northern hemisphere and not from the Arctic, where methane from the melting of permafrost and hydrates has long been a concern. Emissions of nitrous oxide have also grown, with the atmospheric concentration in 2012 at 325.1 parts per billion, 120% above pre-industrial levels.

 

 

http://www.bbc.co.uk/news/science-environment-24833148

 

Also:

 

http://www.reuters.com/article/2013/11/06/environment-greenhouse-idUSL5N0IR1PM20131106

 

WMO bulletin in .pdf format for download:

 

http://www.wmo.int/pages/prog/arep/gaw/ghg/documents/GHG_Bulletin_No.9_en.pdf

[knocker]

From mobile solar to low-risk homes, climate action is underway - UN

LONDON (Thomson Reuters Foundation) – When remote mining camps in Mongolia’s south Gobi desert need energy, they rent diesel generators. But rented solar arrays can provide energy 30 percent cheaper, while producing no carbon emissions, an entrepreneur says.

 

The solar rental model, with no upfront investment costs, makes “a solar farm cheap up front and cheaper to run. The payback time is zero. You immediately start saving from day one,†said Erwin Spolders, whose mobile solar rental company, France-based Redavia, is about to place its first solar arrays in the Gobi and at a Tanzania gold mine.

 

 

http://www.trust.org/item/20131106135632-2ndbe/?source=hptop