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Explaining climate change science & rebutting global warming misinformation

Scientific skepticism is healthy. Scientists should always challenge themselves to improve their understanding. Yet this isn't what happens with climate change denial. Skeptics vigorously criticise any evidence that supports man-made global warming and yet embrace any argument, op-ed, blog or study that purports to refute global warming. This website gets skeptical about global warming skepticism. Do their arguments have any scientific basis? What does the peer reviewed scientific literature say?


The 97% v the 3% – just how much global warming are humans causing?

Posted on 15 September 2014 by dana1981

A pair of climate scientists recently had a dispute regarding how much global warming humans are responsible for. Gavin Schmidt from Nasa represented the consensus of 96–97% of climate experts in arguing that humans have been the dominant cause of global warming since 1950, while Judith Curry from Georgia Tech represented the opinions of 2–4% of climate experts that we could be responsible for less than half of that warming.

Curry is to be the featured speaker on this subject at a National Press Club event tomorrow hosted by the Marshall Institute; a right-wing thinktank that has spread misinformation about the dangers of smoking, ozone depletion, acid rain, DDT, and now climate change. She may also discuss the subject at an event next week hosted by the fossil fuel-funded right-wing think tank Texas Public Policy Foundation (TPPF).

The exchange between Schmidt and Curry can be read on RealClimate – a blog run by climate scientists. The discrepancy in both the quantity and quality of the supporting evidence used by each scientist was one of the most telling aspects of their debate.

For his part, Schmidt referenced the most recent IPCC report. The IPCC summarises the latest and greatest climate science research, so there is no better single source. The figure below from the IPCC report illustrates why 96–97% of climate science experts and peer-reviewed research agree that humans are the main cause of global warming.

The black bar indicates the amount of global surface warming observed from 1951 to 2010. The green bar shows the amount of warming caused by human greenhouse gas emissions during that time. The yellow is the influence from other human effects (mainly cooling from human sulfate aerosol emissions, which scatter sunlight), and the orange is the combined human effect. Below those are the contributions from external natural factors (mainly the sun and volcanoes) and from natural internal variability (mainly ocean cycles), while the whiskers show the uncertainty range for each.

IPCC AR5 Figure 10.5: Assessed likely ranges (whiskers) and their mid-points (bars) for attributable warming trends over the 1951–2010 period due to well-mixed greenhouse gases, other anthropogenic forcings (OA), natural forcings (NAT), combined anthropogenic forcings (ANT) and internal variability. The HadCRUT4 observations are shown in black with the 5 to 95% uncertainty range due to observational uncertainty in this record. IPCC AR5 figure 10.5: Likely ranges (whiskers) and their mid-points (bars) for attributable warming trends over the 1951–2010 period due to greenhouse gases, other anthropogenic forcings (OA), natural forcings (NAT), combined anthropogenic forcings (ANT) and internal variability. The HadCRUT4 observations are shown in black.



2014 SkS Weekly Digest #37

Posted on 14 September 2014 by John Hartz

SkS Highlights

97 hours of consensus: caricatures and quotes from 97 scientists by John Cook attracted the most comments of the articles posted on SkS during the past week. In addition, the 97 Hours campaign was widely acclaimed and promoted by numerous individuals and organizations throughout the world — see the SkS in theNews section of this Digest for details.

El Niño Watch

Long-term weather forecasters say it is now unlikely that a strong El Niño will develop this fall, dimming hopes in California for heavy rains that might bring relief from a severe drought.

In its latest monthly forecast, the federal Climate Prediction Center in College Park, Md., said that while there was still about a two in three chance that El Niño would develop, perhaps in the next two months, it would most likely be weak.

Hopes for a Strong El Niño Fade in California by Henry Fountain, New York Times, Sep 9, 2014

Toon of the Week

 2014 Toon 37



2014 SkS Weekly News Roundup #37B

Posted on 13 September 2014 by John Hartz

Agribusiness drives most illegal deforestation

Everyday products like beef, soy and palm oil already are widely blamed for spurring massive losses of the world's tropical forests. These products are also frequently linked to clearing that takes place in spite of local laws enacted to protect these forests.

But a new report from the environmental nonprofit Forest Trends for the first time attempts to quantify exactly how much of the world's illegal deforestation takes place to make way for palm oil plantations, cattle ranching, soy cultivation and other agricultural commodities.

The research team concluded that between 63 and 75 percent of global deforestation between 2000 to 2012 took place to make way for commercial agriculture. Of this, the authors found, 36 to 65 percent was illegal—the result of fraudulent licenses, destructive clearing techniques or other activities formally prohibited—but often overlooked—by local governments. Forest Trends estimates that the international trade of such products is worth an estimated $61 billion each year.

Agribusiness Drives Most Illegal Deforestation by Elizabeth Harball and Climate Wire/Scientific American, Sep 11, 2014



Thousands of ‘Nameless Short-Lived Lakes’

Posted on 12 September 2014 by greenman3610

This is a re-post from Yale Climate Connections

This month’s Yale Climate Connections “This Is Not Cool” video by independent videographer Peter Sinclair presents images from a research group’s summer of 2014 “Dark Snow” project in Greenland.

“Thousands of nameless short-lived lakes” increasingly reflect “a doubling of the mass loss rate” of Greenland ice over the past decade, says Professor Jason Box, of the Geological Survey of Denmark and Greenland. He says the same holds true for Antarctica.

Damage to the base of the ice sheet and in deep interior areas are unprecedented over at least the past 10,000 years, says glaciologist Alun Hubbard of Aberstwyth University in Wales.

Because of their dark color relative to the surrounding ice sheet, the short-lived lakes absorb sun light… “they’re like big solar collectors,” says Box. He adds the lakes are increasing in size and number.

Rushing water plunging deep through moulins deliver warmth “to regions that have been frozen solid for many millennia,” says Sinclair, who participated in the research trip and did extensive video work while there. That lubricates the ice sheet flow and softens the ice, leading it to flow faster under its own weight, Box explains. One result: more ice bergs calving-off at the glacier front, accelerating ice loss.

Box says Greenland’s sea level contribution has increased from one-half millimeter per year 10 years ago to one millimeter now. He says that loss rate is expected to double every five to 12 years. The next decade Greenland’s losing two millimeters a year, the one after that four millimeters per year. By the end of the century, at that rate, Greenland alone would be accounting for about one meter per year… “just from Greenland.”



2014 SkS Weekly News Roundup #37A

Posted on 11 September 2014 by John Hartz

97%, 97 hours, 97 climate scientists

Global warming is real. Climate change is occurring faster than any time in recorded history. Humans dumping carbon dioxide into the air is to blame.

In the scientific community, those statements are not controversial at all. A solid 97% of climate scientists doing active research into the matter agree on them.

Politically, though, it’s a different story. Only about half the American public think global warming is man-made, and only a fraction of them know that there is overwhelming scientific consensus on it.

To raise both ratios, the wonderful website Skeptical Science has started a great campaign: “97 Hours of Consensus”. Every hour, for just over four days, a cartoon caricature of a different climate scientist will be posted along with a short, pithy quotation about the current understanding on global warming. The campaign started Sunday morning (Sep. 7), so it’s well along now. It started with Dr. Michael Mann, creator of the Hockey Stick graph showing that sudden warming is recent and catastrophic:

97%, 97 Hours, 97 Climate Scientists by Phil Plait, Bad Astronomy, Slate, Sep 9, 2014



Record Greenhouse Gas Levels Impact Atmosphere and Oceans

Posted on 11 September 2014 by Guest Author

This is a WMO press release

Geneva, 9 September 2014 (WMO) – The amount of greenhouse gases in the atmosphere reached a new record high in 2013, propelled by a surge in levels of carbon dioxide.  This is according to the World Meteorological Organization’s annual Greenhouse Gas Bulletin, which injected even greater urgency into the need for concerted international action against accelerating and potentially devastating climate change.

The Greenhouse Gas Bulletin showed that between 1990 and 2013 there was a 34% increase in radiative forcing – the warming effect on our climate – because of long-lived greenhouse gases such as carbon dioxide (CO2), methane and nitrous oxide.

In 2013, concentration of CO2 in the atmosphere was 142% of the pre-industrial era (1750), and of methane and nitrous oxide 253% and 121% respectively.

The observations from WMO’s Global Atmosphere Watch (GAW) network showed that CO2 levels increased more between 2012 and 2013 than during any other year since 1984. Preliminary data indicated that this was possibly related to reduced CO2 uptake by the earth’s biosphere in addition to the steadily increasing CO2 emissions.

The WMO Greenhouse Gas Bulletin reports on atmospheric concentrations – and not emissions - of greenhouse gases. Emissions represent what goes into the atmosphere. Concentrations represent what remains in the atmosphere after the complex system of interactions between the atmosphere, biosphere and the oceans. About a quarter of the total emissions are taken up by the oceans and another quarter by the biosphere, reducing in this way the amount of CO2 in the atmosphere.

The ocean cushions the increase in CO2 that would otherwise occur in the atmosphere, but with far-reaching impacts. The current rate of ocean acidification appears unprecedented at least over the last 300 million years, according to an analysis in the report.

“We know without any doubt that our climate is changing and our weather is becoming more extreme due to human activities such as the burning of fossil fuels,” said WMO Secretary-General Michel Jarraud.



In the Years of Living Dangerously, Part 3

Posted on 10 September 2014 by John Abraham

In this last post about the Years of Living Dangerously series, I focus on episode 8 (A Dangerous Future). This episode follows Matt Damon, Thomas Friedman and Michael Hall as they all become investigative journalists in different parts of the world. Each story is individually, is impactful but when they are juxtaposed, the connections between climate change and human welfare are obvious.

We meet Michael Hall as he disembarks in Bangladesh on a mission to find impacts of climate change on workers in developing economies. He meets with Bangladeshi journalists and top climate scientists and we learn about the tremendous impact of large and increasing storms on persons near the coast. These coastal people, who often lack robust infrastructure, face tough life choices following devastating storms. Scientific literature shows we expect approximately 3 feet of sea level rise by the end of the century. Because of the very flat topology of Bangladesh, approximately 17% of the land area will be inundated with sea water – 20 million people will be (and already are being) displaced. They are some of the world’s first climate refugees.

Bangladesh is a country the size of Iowa with half the population of the United States – think of that population density. What happens as increasing numbers of coastal communities are forced to migrate? What Michael Hall learns is that climate migrants are not a prediction of the future, rather a fact of the present. We meet some of the migrants who are forced to leave their home communities to seek dangerous work elsewhere. First-hand evidence shows that climate change stacks the deck against people in the developing world.



Cutting Emissions Pays for Itself

Posted on 9 September 2014 by Guest Author

This is a re-post from Audrey Resutek at the MIT Joint Program on the Science and Policy of Global Change 

Study finds that savings from healthier air can make up for some or all of the cost of carbon reduction policies. 

Lower rates of asthma and other health problems are frequently cited as benefits of policies aimed at cutting carbon emissions from sources like power plants and vehicles, because these policies also lead to reductions in other harmful types of air pollution.

But just how large are the health benefits of cleaner air in comparison to the costs of reducing carbon emissions? MIT researchers looked at three policies achieving the same reductions in the United States, and found that the savings on health care spending and other costs related to illness can be big—in some cases, more than 10 times the cost of policy implementation.

“Carbon-reduction policies significantly improve air quality,” says Noelle Selin, an assistant professor of engineering systems and atmospheric chemistry at MIT, and co-author of a study published in Nature Climate Change. “In fact, policies aimed at cutting carbon emissions improve air quality by a similar amount as policies specifically targeting air pollution.”

Selin and colleagues compared the health benefits to the economic costs of three climate policies: a clean-energy standard, a transportation policy, and a cap-and-trade program. The three were designed to resemble proposed U.S. climate policies, with the clean-energy standard requiring emissions reductions from power plants similar to those proposed in the Environmental Protection Agency’s Clean Power Plan.

Health savings constant across policies

The researchers found that savings from avoided health problems could recoup 26 percent of the cost to implement a transportation policy, but up to to 10.5 times the cost of implementing a cap-and-trade program. The difference depended largely on the costs of the policies, as the savings — in the form of avoided medical care and saved sick days — remained roughly constant: Policies aimed at specific sources of air pollution, such as power plants and vehicles, did not lead to substantially larger benefits than cheaper policies, such as a cap-and-trade approach.



In the Years of Living Dangerously, Part 2

Posted on 8 September 2014 by John Abraham

This episode brings us away from the world of hard science a bit and into a realm of personality and ideology. The episode provides an intimate view of family relationships that are repeated across the nation and the world. Dinner table conversations that are played out with different characters, in a different cities, but with similar results.

This is the setting for the next Years of Living Dangerously episode I am reviewing. In part of this episode, we travel with Ian Somerhalder to South Carolina where we meet a young, smart, and dedicated Anna Jane Joyner. She is the daughter of megachurch leader Rick Joyner who, shall we say, does not share her views on climate change.

We quickly see that Anna has indefatigable courage and persistence. Not only by her dedication but because her pathway has lead her into the heart of the unconvinced. It has led her on a path of conflict with her own father. It no doubt has shaken her entire life. Who else can say that?

Anna works for the growing and ever important creation-care movement. This movement just makes sense. It is an appeal to people of faith, often evangelicals, who are notably sceptical about human-caused climate change. Her appeal is based on a biblical message that we are to be stewards of the Earth.



2014 SkS Weekly Digest #36

Posted on 7 September 2014 by John Hartz

SkS Highlights

 97 Hours Banner

97 hours of consensus: caricatures and quotes from 97 scientists by John Cook 

El Niño Watch

For months now, the tropical Pacific Ocean has been flirting with blossoming into a full-fledged El Niño state: Waters off the coast of South America have warmed, a hallmark of the climate phenomenon, but then cooled, only to warm once again. Winds, which normally blow east-to-west have made tentative moves in the other direction, another key criteria, but the bottom line is that the whole El Niño package hasn’t come together.

So, is this El Niño going to happen or not?

“Most likely” is the answer from forecasters with the National Oceanic and Atmospheric Administration’s Climate Prediction Center and the International Research Institute for Climate and Society at Columbia University, who issue monthly forecasts.

El Nino Watch: 6 Months and Still Counting by Andrea Thompson, Climate Central, Sep 4, 2014 

Toon of the Week

 2014 Toon 36

h/t to I Heart Climate Scientists



97 hours of consensus: caricatures and quotes from 97 scientists

Posted on 7 September 2014 by John Cook

Climate scientists from across the globe feature in our 97 Hours of Consensus campaign addressing one of the most significant and harmful myths about climate change. Each hour, beginning at 9am Sunday EST, September 7th, we'll publish a statement and playful, hand-drawn caricature of a leading climate scientist. Each caricature lists the scientists’ name, title, expertise and academic institution.

97 Hours of Consensus communicates the fact that 97% of climate scientists have concluded that humans are causing global warming. The research, conducted by scientists at The University of Queensland’s Global Change Institute, University of Reading, Michigan Technological University and Memorial University of Newfoundland found that 97% of relevant climate papers endorsed human-caused global warming. The paper was published in the academic journal Environmental Research Letters in May 2013.



2014 SkS Weekly News Roundup #36B

Posted on 6 September 2014 by John Hartz

5 reasons to watch NYC’s Climate Summit

On September 23, heads of state and leaders in finance, business and civil society will gather in New York City for the United Nations Climate Summit 2014. The summit is a critical milestone on the path to addressing the global threat of climate change. UN Secretary-General Ban Ki-moon organized the high-level meeting to re-engage world leaders to spur climate action on national and international stages.

Tens of thousands of concerned citizens are seizing the opportunity, organizing the largest climate march in history. During summit week, hundreds of organizations have arranged speeches, documentary film showings, and other gatherings to present the overwhelming evidence of the consequences of climate change and cost-effective solutions to address the problem. New scientific research like the National Climate Assessment and the latest IPCC reports have illuminated the risks from carbon pollution, while new economic analysis including WRI’s upcoming New Climate Economy report will dispel the notion that climate action will slow economic growth.

Yet this is hardly the first time governments have convened to counter climate change. So why is this summit worth watching? 

5 Reasons To Watch NYC’s Climate Summit by Jennifer Morgan, World Resources Institute (WRI), Sep 2, 2014



Rising Ocean Temperature: Is the Pacific Ocean Calling the Shots?

Posted on 5 September 2014 by Rob Painting

Key Points:
  • Even though the ocean has warmed strongly, global 'surface' warming in the 21st century has been slower than previous decades. One of the prime suspects for this has been an increase in trade winds which help to mix heat into the subsurface ocean - part of a natural oscillation known as the Interdecadal Pacific Oscillation (IPO).
  • A recently published research paper, Chen & Tung (2014), claim that changes in the saltiness (salinity) of seawater in the North Atlantic is responsible for the decadal-scale variation in ocean heat uptake, rather than the IPO, as increased saltiness makes surface water denser and therefore facilitates the sinking of water transported poleward.
  • Chen & Tung's  own analysis, however, shows that North Atlantic Ocean warming peaked in 2006 and has declined since that time whereas deep ocean warming, as a whole, has not. 
  • This new research affirms earlier work (Meehl et [2011] & Meehl et al [2013]) implicating the increased, albeit likely temporary, mixing of heat down into deeper ocean layers as a key contributor to the slower rate of surface warming in the 21st century.


Figure 1 - Ocean heating rates for the global ocean and individual ocean basins down to 1500 metres. The coloured lines represent the various ocean layers. Notably the observations show greater warming in the deeper layers, with the strongest deep ocean warming occurring in the Atlantic & Southern Ocean. Image from Chen & Tung (2014)

Ocean Warming: Background Context

The oceans are currently warming because of the extra greenhouse gases that human industrial activity has added to the atmosphere. Not only do greenhouse gases trap heat in the atmosphere, but they alter the gradient in the cool-skin layer of the ocean, which results in less heat escaping the ocean and thus warming over time.

Despite this increasing greenhouse gas-induced warming of the oceans, the ocean doesn't warm in a linear manner due to a number of factors, one of these being a natural decadal-scale variation in the way heat is mixed into the oceans by winds - the Interdecadal Pacific Oscillation (IPO). The IPO is, essentially, an oscillation in the strength of winds (primarily the tropical Trade Winds) which promote the mixing of heat down into the ocean interior and thus affect sea surface temperatures.

The main mechanism for wind-driven mixing into the deep ocean (down to around 2000 metres) is via convergence of warm tropical surface water in the subtropical ocean gyres. These subtropical ocean gyres are large rotating masses of surface water which occupy the mid-latitudes of each ocean basin. Surface water is transported to the subtropical gyres because of the winds drag on the sea surface. Rather than travelling in the same direction as the trade winds, the net flow of water in the surface layers affected by the wind are 90 degrees to the direction of travel - to the right in the Northern Hemisphere, and to the left in the Southern Hemisphere. This occurs because the Earth is rapidly rotating beneath the surface currents and results in an 'apparent deflection'. The impact this has is very real however.

Figure 2 - annual wind stress (i.e. the average wind) for the global oceans between 1982-2004. The lime green splotches near the equator in each hemisphere depict the trade winds, and the areas from about 35° poleward show dominant mid-latitudes westerlies. From the location and direction of these dominant winds we get convergence of ocean currents at around 30-40° in each hemisphere. Image from NOAA GODAS. 

As the warm tropical surface waters travel poleward they encounter an equatorward flowing current created by the mid-latitude westerlies and this surface convergence causes the centre of the gyre to pile up water mass. With nowhere else to go, the surface convergence forms a vertical current known as Ekman pumping (Ekman [1905]) which transports heat down to the depths. In order to maintain a balance, there is a return flow of water, at depth, back toward the equator and poles. Note that there is also poleward transport in the shallow currents at the western edge of each subtropical ocean gyre - known as western boundary currents.     

Figure 3 - A strengthening of the gyre circulation between 2004-2008 is indicated by the gain in steric height for the 500 decibar pressure level (near 500m) relative to 2000 decibar (near 2000m). Image adapted from Roemmich & Gilson (2009).       

The Atlantic Ocean: A Driver, or a Passenger?

Chen and Tung (2014) analyse the ocean heat content data maintained by a Japanese research group, Ishii et al (2005), and make a number of statements about the cause of multi-decadal fluctuations in ocean heat mixing rates. Chief among these claims is that the change in salinity in the North Atlantic ocean is responsible for the decadal fluctuations, not changes in the trade winds and mid-latitude westerlies (the IPO) - as suggested by Meehl et al (2011), Meehl et al (2013) and England et al (2014) for instance. One of the rationales given by Chen & Tung for dismissing the role of the IPO in deep ocean warming is the expectation that the Pacific Ocean basin should have warmed more during the current (2000-to present) IPO negative phase. In a press release Tung states:



When their research has social implications, how should climate scientists get involved?

Posted on 4 September 2014 by John Abraham

First, at the end of this post is a question to my readers wherein I ask for feedback. So, please read to the end.

Most scientists go into their studies because they want to understand the world. They want to know why things happen; also how to describe phenomena, both mathematically and logically. But, as scientists carry out their research, often their findings have large social implications. What do they do when that happens?

Well traditionally, scientists just “stick to the facts” and report. They try to avoid making recommendations, policy or otherwise, that are relevant to the findings. But, as we see the social implications of various issues grow larger (environmental, energy, medical, etc.) it becomes harder for scientists to sit out in more public discussions about what should be done. In fact, researchers who have a clear handle on the issue and the pros and cons of different choices have very valuable perspectives to provide society.

But what does involvement look like? For some scientists, it may be helping reporters gather information for stories that may appear online, in print, radio, or television. In another manifestation, it might be writing for themselves (like my blog here at the Guardian). Others may write books, meet with legislators, or partake in public demonstrations.

Each of these levels of engagement has professional risks. We scientists need to protect our professional reputations. That reputation requires that we are completely objective in our science. As a scientist becomes more engaged in advocacy, they risk being viewed by their colleagues as non-objective in their science.

Of course, this isn’t true. It is possible (and easy) to convey the science but also convey the importance of taking action. I do this on a daily basis. But I will go further here. It is essential for scientists to speak out. With the necessary expertise to make informed decisions, it is out obligation to society. Of course, each scientist has to decide how to become engaged. We don’t get many kudos for engagement, it takes time and money out of our research, you will never get tenured for having a more public presence, and you will likely receive po)rly-writen hate mail – but it still is needed for informed decision making.



2014 SkS Weekly News Roundup #36A

Posted on 3 September 2014 by John Hartz

Antarctic sea-level surge linked to icesheet loss

Sea levels around Antarctica have been rising a third faster than the global average, a clear sign of high melt water runoff from the continent's icesheet, say scientists.

Satellite data from 1992 to 2011 found the sea surface around Antarctica's coast rose by around eight centimetres in total compared to a rise of six centimetres for the average of the world's oceans, they report in the journal Nature Geoscience.

The local increase is accompanied by a fall in salinity at the sea surface, as detected by research ships.

These dramatic changes can only be explained by an influx of freshwater from melting ice, say the study's authors.

Antarctic sea-level surge linked to icesheet loss by AFP/ABC Science, Sep 1, 2014



Climate sceptics see a conspiracy in Australia's record breaking heat

Posted on 3 September 2014 by Guest Author

You could cut the triumphalism on the climate science denialist blogs right now with a hardback copy of George Orwell’s Nineteen Eighty-Four.

Their unbridled joy comes not in the wake of some key research published in the scientific literature but in the fact that a climate sceptic has got a mainstream newspaper to give their conspiracy theory another airing.

The sceptic in question is Dr Jennifer Marohasy, a long-time doubter of human-caused climate change whose research at Central Queensland University (CQU) is funded by another climate change sceptic.

I choose the Nineteen Eighty-Four analogy in my introduction because it is one of Marohasy’s favourites. She likes to compare the work of the Bureau of Meteorology (BoM) to the various goings on in Orwell’s fictional dystopian novel.

The conspiracy theory is that BoM is using a technique to selectively tamper with its temperature data so that it better fits with the global warming narrative.

The people at NASA are in on it too.

Now the great thing about conspiracy theories is that, for believers, attempts to correct the record just serve to reinforce the conspiracy. Like a video clip of the moon landing on a constant loop, the whole thing feeds back on itself.

Correspondence posted on Marohasy’s blog shows she has been pushing her claims for months that BoM has “corrupted the official temperature record so it more closely accords with the theory of anthropogenic global warming”, according to a letter she wrote to Liberal Senator Simon Birmingham, whose parliamentary secretary portfolio includes responsibility for the agency.

Marohasy lays it on thick in the letter, accusing the bureau of engaging in “propaganda” and littering the text with claims of “corruption”.



Fire and water – how global warming is making weather more extreme and costing us money

Posted on 2 September 2014 by dana1981

Connecting the dots between human-caused global warming and specific extreme weather events has been a challenge for climate scientists, but recent research has made significant advances in this area. Links have been found between some very damaging extreme weather events and climate change.

For example, research has shown that a “dipole” has formed in the atmosphere over North America, with a high pressure ridge off the west coast, and a low pressure trough over the central and eastern portion of the continent.

Departure of the November 2013 – January 2014 250 hPa geopotential height from the normal climatology. Departure of the November 2013 – January 2014 250 hPa geopotential height from the normal climatology. Source: Wang et al. (2014), Geophysical Research Letters Photograph: Wang et al. (2014), Geophysical Research Letters

These sorts of pressure ridges in the atmosphere are linked to “waves” in the jet stream. Research has shown that when these jet stream waves form, they’re accompanied by more intense extreme weather. The high pressure zone off the west coast or North America has been termed the “Ridiculously Resilient Ridge” due to its persistence over the past two years. It’s been the main cause of California’s intense drought by pushing rain storms around the state.

California drought as of 26 August 2014.  58% of the state is in 'exceptional drought' conditions. California drought as of 26 August 2014. 58% of the state is in ‘exceptional drought’ conditions. Source: United States Drought Monitor



Keystone XL: Oil Markets and Emissions

Posted on 1 September 2014 by Andy Skuce

  • Estimates of the incremental emission effects of individual oil sands projects like the Keystone XL (KXL) pipeline are sensitive to assumptions about the response of world markets and alternative transportation options.

  • A recent Nature Climate Change paper by Erickson and Lazarus concludes that KXL may produce incremental emissions of 0-110 million tonnes of CO2 per year, but the article has provoked some controversy.

  • Comments by industry leaders and the recent shelving of a new bitumen mining project suggest that the expansion of the oil sands may be more transportation constrained and more exposed to cost increases than is sometimes assumed.

  • Looking at the longer-term commitment effects of new infrastructure on cumulative emissions supports the higher-end incremental estimates.

President Obama (BBC) has made it clear that the impact of the Keystone XL (KXL) pipeline on the climate will be critical in his administration’s decision on whether the pipeline will go ahead or not.  However, different estimates of the extra carbon emissions that the pipeline will cause vary wildly. For example, the consultants commissioned by the US State Department estimated that the incremental emissions would be 1.3 to 27.4 million tonnes of CO2 (MtCO2) annually. In contrast, John Abraham, writing in the Guardian (and again more recently), estimated that the emissions would be as much as 190 MtCO2 annually, about seven times the State Department’s high estimate (calculation details here).

The variation in the estimates arises from the assumptions made. The State Department consultants assumed that the extra oil transported by the pipeline would displace oil produced elsewhere, so that we should only count the difference between the life-cycle emissions from the shut-in light oil and those of the more carbon-intensive bitumen. In addition, they estimated that not building KXL would mean that bitumen would instead be transported by rail, at slightly higher transportation costs. Abraham simply totted up all of the production, refining and consumption emissions of the 830,000 barrels per day (bpd) pipeline capacity and did not consider any effect of the extra product on world oil markets.

Neither set of assumptions is likely to be correct. Increasing the supply of any product will have an effect on a market, lowering prices and stimulating demand (consumption) growth. Lower prices will reduce supply somewhere.  The question is: by how much?

An interesting new paper in Nature Climate Change (paywalled, but there is an open copy of an earlier version available here) by Peter Erickson and Michael Lazaruares ,attempts to answer this question. The authors are based in the Seattle office of the Stockholm Environment Institute (SEI).



2014 SkS Weekly Digest #35

Posted on 31 August 2014 by John Hartz

SkS Highlights

Michael J.I. Brown's guest post, What I learned from debating science with trolls attracted the highest number of comments of the articles posted on SkS during the past week. Many commenters provided their own example of lessons learned. The post and the commentary make for very interesting reading indeed.

Generating the second highest number of comments was Athabasca Glacier: a tragic vanishing act by Andy Skuce.  Coming in a strong third was John Abraham's US State Department underestimates carbon pollution from Keystone XL.

El Niño Watch

Pacific watch: Is El Niño finding its second wind? by Roz Pidcock, The Carbon Brief, Aug 22, 2014 

Toon of the Week

 2014 Toon 35

h/t to I Heart Climate Scientists



2014 SkS Weekly News Roundup #35B

Posted on 30 August 2014 by John Hartz

Antarctic riddle: How much will the South Pole melt?

One of the biggest question marks surrounding the fate of the planet’s coastlines is dangling from its underbelly. 

The melting of the Antarctic ice sheet has long been a relatively minor factor in the steady ascent of high-water marks, responsible for about an eighth of the 3 millimeters of annual sea-level rise. But when it comes to climate change, Antarctica is the elephantine ice sculpture in the boiler room. The ice sheet is so massive that its decline is, according to the recent Intergovernmental Panel on Climate Change assessment, “the largest potential source” of future sea level rise. Accurately forecasting how much of it will be unleashed as seawater, and when that will happen, could help coastal communities plan for surging flood risks.

study published Aug. 14 in Earth System Dynamics — one that took more than 2 years and 50,000 computer simulations to complete, combining information from 26 atmospheric, oceanic, and ice sheet models from four polar regions — has helped scientists hone their forecasts for this century’s Antarctic thaw. And the results of the global research effort were more sobering than the findings of most of the more limited studies that came before it.

Antarctic Riddle: How Much Will the South Pole Melt? by John Upton, Climate Central, Aug 25, 2014

As Louisiana sinks and sea levels rise, the State is drowning. Fast.

In just 80 years, some 2,000 square miles of its coastal landscape have turned to open water, wiping places off maps, bringing the Gulf of Mexico to the back door of New Orleans and posing a lethal threat to an energy and shipping corridor vital to the nation’s economy.

And it’s going to get worse, even quicker.

Scientists now say one of the greatest environmental and economic disasters in the nation’s history is rushing toward a catastrophic conclusion over the next 50 years, so far unabated and largely unnoticed.

At the current rates that the sea is rising and land is sinking, National Oceanic and Atmospheric Administration scientists say by 2100 the Gulf of Mexico could rise as much as 4.3 feet across this landscape, which has an average elevation of about 3 feet. If that happens, everything outside the protective levees — most of Southeast Louisiana — would be underwater. 

As Louisiana Sinks And Sea Levels Rise, The State Is Drowning. Fast. by Bob Marshall, The Lens, Brian Jacobs and Al Shaw, ProPublica, The Huffington Post, Aug 28, 2014



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