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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Climate Hustle

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?


Global weirding with Katharine Hayhoe: Episode 2

Posted on 27 October 2016 by Guest Author

Just how long have we known about climate change anyways?

Global Weirding is produced by KTTZ Texas Tech Public Media and distributed by PBS Digital Studios. New episodes every other Wednesday at 10 am central. Brought to you in part by: Bob and Linda Herscher, Freese and Nichols, Inc, and the Texas Tech Climate Science Center.



Tracking the 2°C Limit - September 2016

Posted on 26 October 2016 by Rob Honeycutt

Septembers GISTemp data is now in so I can update the 2°C Limit chart. (Full page image here.) The Sept anomaly came in at 0.91°C, baselined to preindustrial that puts last month at 1.168°C. 

Now that anomalies have dropped back down closer to the long term trend, the latest plots are hard to pick out. Here's September:



'The atmosphere is being radicalized' by climate change

Posted on 24 October 2016 by dana1981

Climate change’s impacts on extreme weather and society are becoming increasingly clear and undeniable. While we are making progress in solving the problem, we’re still moving too slowly, and one of the two political parties governing the world’s strongest superpower continues to deny the science. This led astrophysicist Katie Mack to make the following suggestion, related to a common refrain from Donald Trump and Republican Party leaders:

Maybe governments will actually listen if we stop saying "extreme weather" & "climate change" & just say the atmosphere is being radicalized

Global warming intensified Hurricane Matthew

Hurricane Matthew set a number of records. Its record-breaking rainfall and storm surge caused historic flooding and destructive winds along the coasts of Florida, Georgia, the Carolinas, and Virginia. Hillary Clinton touched upon the science linking global warming and hurricane impacts in a recent speech in Florida:



2016 SkS Weekly Climate Change & Global Warming Digest #43

Posted on 23 October 2016 by John Hartz

Story of the Week... SkS Highlights...La Niña Update... Toon of the Week... Quote of the Week... Graphic of the Week... SkS in the News... SkS Spotlights... Video of the Week... Coming Soon on SkS... Poster of the Week... Climate Feedback Reviews... SkS Week in Review... 97 Hours of Consensus...

Story of the Week...

After this election, it’s going to be difficult to believe that concern about global warming has finally reached critical mass. And I suspect that won’t change until its effects are knocking at our front door. Many Americans are still detached enough from consequences like drought, wildfire, and species extinction to hold onto a sliver of cognitive dissonance, and perhaps our candidates know that.

“There are too many good reasons why we humans resist the many sad facts of climate disruption, the ‘global weirding,’” said Per Espen Stoknes, author of What We Think About When We Try Not to Think About Global Warming.

“It finally boils down to the question, Why bother? Humans will act for the long-term when conducive conditions are in place.”

Remember When We Thought Climate Change Would Matter This Election? by Sarah Emerson, Motherboard, Oct 20, 2016 

SkS Highlights...

Using the metric of comments garnered, Insight into the scientific credibility of The Guardian climate coverage by Climate Feedback is the most popular of the articles posted on SkS during the past week. 

La Niña  Update...

Many have doubted forecasts calling for the onset of the first La Niña in almost five years, believing that its failure to materialize in convincing fashion last summer - as originally predicted - means that it may be off the table for 2016-17.

But in recent weeks, the oceans and atmosphere have been pulling everything into place to facilitate a potentially stronger La Niña than previously thought, so those who follow commodities markets may want to take a second look.

Last Thursday, the U.S. Climate Prediction Center reissued the La Niña watch that was removed in early September. The watch indicates that conditions are favorable for the phenomenon’s development within the next six months. 

Stronger-than-expected La Niña may be brewing, Op-ed by Karin Braun, Reuters, Oct 20, 2016

Toon of the Week...

 2016 Toon 43



2016 SkS Weekly Climate Change & Global Warming News Roundup #43

Posted on 22 October 2016 by John Hartz

A chronological listing of the news articles posted on the Skeptical Science Facebook page during the past week.

Sun Oct 16, 2016



Global warming continues; 2016 will be the hottest year ever recorded

Posted on 21 October 2016 by John Abraham

We know the world is warming – no factor can explain it aside from human emissions of greenhouse gases. Despite this, people who deny the basic facts of climate change have tried to argue that the Earth is either not warming or is only slowly heating. Well that just isn’t true anymore. The last three years are the nail in the coffin of the deniers of climate change. We have enough data this year to call 2016 as the hottest year ever record – and we have three more months left to go.

So, just how hot is 2016? Well my early predictions are shown in the graph below. I have taken temperature data from NASA and superimposed my predictions for 2016 – it isn’t even close. And by the way, it doesn’t matter whose data you use (NASA, NOAA, JMA, Hadley Centre) the results are the same. 2016 is going to blow 2015 out of the water.


A few things to note. First, these temperatures are surface temperatures that are taken across the globe. But, you can measure temperatures elsewhere and see the same result. Most importantly, measurements in the oceans, where 93% of the extra heat is stored are the best proof of global warming. I recently coauthored an open-access paper on this very topic which interested readers can get here.



Join the self-paced version of Denial101x - Making sense of climate science denial!

Posted on 20 October 2016 by BaerbelW

The next run of our free online course, Making Sense of Climate Science Denial, started on Oct. 18 and will be open until March 7, 2017 as a self-paced course. This means that there are no deadlines apart from the final day of the MOOC and that you can work through all of the material as your time allows. If you participated in one of the earlier iterations but missed some deadlines, this is the opportunity to see it through.

The MOOC (Massive Open Online Course) is a collaboration between Skeptical Science and The University of Queensland, that takes an interdisciplinary look at climate science denial. We explain the psychological drivers of denial, debunk many of the most common myths about climate change and explore the scientific research into how to respond to climate misinformation.



No longer taken seriously, we're seeing the last gasp of climate denial groups

Posted on 19 October 2016 by dana1981

The Global Warming Policy Foundation (GWPF) is an anti-climate policy advocacy group in the UK that often releases misleading scientific “reports.” The group also hosts annual lectures, and this year, they booked a room at the Royal Society. Many members of the Royal Society expressed concern that the GWPF would exploit the organization’s credibility, and asked that the event be cancelled

The Royal Society’s governing council met and decided to allow the event to proceed, for fear that cancellation would give it “an unwarranted higher profile.” As a spokesperson for the Royal Society told DeSmog UK:

The evidence shows us that the earth is warming and that recent warming is largely caused by human activities. Once that is accepted, there is scope for debate on the policy responses and that is the area that the GWPF claims to be interested in.

If the GWPF uses this opportunity to misrepresent the scientific evidence it would undermine the legitimacy of its views on policy responses to climate change.

The lecture was delivered by writer Matt Ridley, and predictably, as is the norm for Ridley, the first three-quarters of his talk indeed misrepresented the scientific evidence. While Ridley doesn’t deny the most basic aspects of human-caused global warming, he is a self-prescribed “lukewarmer;” a group that falls into the category of Stage 3 climate denial.

Ridley’s lecture is a 5,600-word Gish Gallop that would require a novel to fully debunk. However, he condensed his main arguments into four key points that are easily refuted:

Why do I think the risk from global warming is being exaggerated? For four principal reasons.

1. All environmental predictions of doom always are;
2. the models have been consistently wrong for more than 30 years;
3. the best evidence indicates that climate sensitivity is relatively low;
4. the climate science establishment has a vested interest in alarm.

We’ve solved previous environmental problems, so let’s not solve global warming?

Ridley’s first argument against the dangers of global warming is incredibly ironic. He claims that we have nothing to worry about because previous “environmental predictions of gloom” were wrong. But the reason his cited predictions of danger didn’t come to fruition, in most cases, is because we took action to stop them.



Insight into the scientific credibility of The Guardian climate coverage

Posted on 18 October 2016 by Guest Author

This is a re-post from Climate Feedback


Over the past two months, Climate Feedback has asked its network of scientists to review 5 widely read articles published by The Guardian. Three were found to be both accurate and insightful. Two were found to contain inaccuracies, false or misleading information, and statements unsupported by current scientific knowledge.

Insightful climate reporting in The Guardian

Climate Feedback’s analysis of The Guardian article written by Damian Carrington and published on September 23, “Greenland’s huge annual ice loss is even worse than thought,” was found to be accurate by all the reviewers.  For instance, Dr. Lauren Simkins qualified it as “a succinct and accurate assessment of past and present ice mass loss from the Greenland Ice Sheet that is supplemented by insightful comments from scientific experts.” Another analysis, of The Guardian’s “Disasters like Louisiana floods will worsen as planet warms, scientists warn,” written by Oliver Milman and published on August 16, rated that article as having “high” scientific credibility, with Dr. Ben Henley noting that

The article is accurate. The issue of increasing precipitation extremes due to climate change is presented well. Heavy precipitation increases have been observed, and are projected to worsen with climate change.

Guests’ misleading claims go unchallenged

By contrast, two articles published in The Guardian’s Saturday interview section and The Observer ranked “low” on Climate Feedback’s “scientific credibility” scale.



Finance for deep-rooted prosperity is coming

Posted on 17 October 2016 by Guest Author

Joseph Robertson is Global Strategy Director for the nonpartisan nonprofit organization Citizens’ Climate Lobby.

“Macrocritical resilience” may be the most mystifying two-word phrase you need to know. Though you may never have heard these two words before, what they describe affects everything you live and strive for. Wonky as it sounds, it is a common sense idea: what generates value is more valuable than what we count in dollars. And yet, it is only in the last few years that we are truly beginning to understand that macrocritical indicators—elements of human experience that shape the health and viability of the overall economy—really do describe how and where value and capability come into being.

On Christmas Eve, 2013, the small island nation of St. Vincent and the Grenadines experienced the most intense rainfall in its history. 15 percent of gross domestic product was wiped out in just a few hours. In 2004, Hurricane Ivan caused $900 million worth of damage in Grenada—more than twice the nation’s GDP. One of the executive directors of the International Monetary Fund noted that when so much value can be lost so suddenly, “you no longer know what the value of a dollar is.”


A team of citizen volunteers provided needed health and recovery support to villages affected by the 2015 earthquake that ravaged Nepal. Climate resilience is partly about ensuring glacial melt and landslides are less of a threat to human populations. Photograph: Nepal chapter of Citizens' Climate Lobby.



2016 SkS Weekly Climate Change & Global Warming Digest #42

Posted on 16 October 2016 by John Hartz

Story of the Week... SkS Highlights...La Niña Update... Toon of the Week... Quote of the Week... Graphic of the Week... SkS in the News... SkS Spotlights... Video of the Week... Coming Soon on SkS... Poster of the Week... SkS Week in Review... 97 Hours of Consensus...

Story of the Week...

Update 15/10/16 — A deal was agreed by almost 200 countries on 15 October 2016. The agreement means that developed countries will start to limit their use of HFCs by at least 10% from 2019. The complex deal also ensures that many developing countries, such as China and some in South America, will freeze their HFC use from 2024. Other developing nations, such as India, Pakistan, Iran, Iraq and the Gulf states, will not freeze their use until 2028. By the late 2040s, all countries are expected to consume no more than 15-20% of their respective baselines. Countries also agreed to additional funding, but the exact amount will be agreed at the next meeting in Montreal in 2017. 

Explainer: Why a UN climate deal on HFCs matters by Sophie Yeo, Carbon Brief, oct 10/15/ 2016

SkS Highlights...

The video, Trailer: Before the Floodby garnered the highest number of comments of the items posted on the SkS website during the past week. Before the Flood is a movie documenting Leonardo DiCaprio meetings with scientists, activists and world leaders to discuss the dangers of climate change and possible solutions.

La Niña Update...

What a difference a month can make! Since my last post, the tropical Pacific has changed gears, and now forecasters think there’s a 70% chance that La Niña conditions will develop this fall. However, any La Niña that develops is likely to be weak, and forecasters aren’t quite as confident that La Niña conditions will persist long enough to be considered a full-blown episode, giving it a 55% chance through the winter.

Antici...pation: October 2016 ENSO forecast by Emily Becker, NOAA's, Oct 13, 2016 

Toon of the Week...

 2016 Toon 42



2016 SkS Weekly Climate Change & Global Warming News Roundup #42

Posted on 15 October 2016 by John Hartz

A chronological listing of the news articles posted on the Skeptical Science Facebook page during the past week.

Sun Oct 9, 2016



Climate scientists published a paper debunking Ted Cruz

Posted on 14 October 2016 by John Abraham

A new study has just appeared in the Journal of Climate which deals with an issue commonly raised by those who deny that human-caused climate change is a serious risk. As I have written many times, we know humans are causing the Earth’s climate to change. We know this for many reasons. 

First, we know that certain gases trap heat; this fact is indisputable. Second, we know that humans have significantly increased the amount of heat-trapping gases in the atmosphere. Again, this is indisputable. Third, we know the Earth is warming (again indisputable). We know the Earth warms because we are actually measuring the warming rate in multiple different ways. Those measurements are in good agreement with each other.

Of course there is other evidence too. For instance, ice loss across the globe is widespread: in the Arctic, the Antarctic ice shelves, Greenland, and from land glaciers. Sea levels are rising as warm water expands in volume and as melt waters flow into the ocean. We are also seeing changes of weather patterns and climatic zones shift. The point is, there is a whole body of evidence that proves the climate is changing and the change is caused largely by human emissions of greenhouse gases.

Over the years, contrarians have looked for evidence that the climate either isn’t changing or the change is not as fast as predicted. Their findings have often been used in the media to suggest that human-caused climate change was not something to worry about. But we’ve seen, over and over and over again, that these contrarian arguments don’t hold up. 

Repeatedly, mainstream scientists have taken these claims seriously and discovered they were just plain wrong. In some cases, the contrarians have made simple arithmetic errors (like mixing up a negative and positive sign in their equations), while in others, they have made more fundamental errors. But regardless, they have been wrong time after time. But whenever they are found to be wrong, they just go and find some new piece of evidence that once again calls into doubt our understanding of the human-climate link. 



Hillary Clinton and Al Gore talk climate and energy in Miami

Posted on 13 October 2016 by Guest Author



Explainer: Paris Agreement on climate change to ‘enter into force’

Posted on 12 October 2016 by Guest Author

This is a re-post from Carbon Brief by Sophie Yeo

The Paris Agreement will formally come into force next month, legally binding countries that have ratified the deal to act on the pledges made last year.

This includes a commitment by every country to prepare increasingly ambitious pledges to tackle greenhouse gas emissions every five years, known as Nationally Determined Contributions.

There were two thresholds that had to be crossed before the deal could come into force: at least 55 countries covering at least 55% of global emissions had to ratify the deal.

The first of these thresholds was passed on 21 September. As of today, 74 countries have ratified the deal. The EU’s fast-tracked ratification, which concluded on 4 October with the European Parliament’s vote in favour, has now pushed the deal over the second threshold.

The deal won’t come into force instantly. The Paris Agreement stipulates that this will happen 30 days after both the thresholds have been crossed. The UN says this will be on 4 November.

But it does mean that it will be in force before countries meet again for their first major UN climate meeting since Paris — and before the US elections on the 8 November.

Unexpected haste

By all accounts, countries have acted with remarkable haste in ratifying the Paris Agreement.

A raft of countries ratified the deal on 22 April, which was the first possible opportunity to do so. These mainly included small island states, whose emissions are negligible in the context of global emissions.

While these early-ratifying small countries helped to inch the agreement towards the first threshold, it was important to bring the big emitters on board to reach the second threshold.

On 3 September, the US and China jointly ratified the agreement. Together they were responsible for 38% of global emissions. This provided a big boost, but not quite enough to tip the total beyond 55%.

For a short time, there was a question mark over how the remainder would be made up, with doubts clouding the will or ability of the remaining big emitters to ratify.



Trailer: Before the Flood

Posted on 11 October 2016 by Guest Author



Caring for Creation makes the Christian case for climate action

Posted on 10 October 2016 by John Abraham

From within this movement, there are huge voices, widely respected by both the scientific and faith communities. Perhaps the best known is Dr. Katharine Hayhoe, a top climate scientist who is also an evangelist Christian. There are other persons and organizations who work similarly to connect these two world viewpoints in a powerful yet common-sense way.

Recently a book has been published by a faith-science duo. That duo is Paul Douglas, respected meteorologist, entrepreneur, Republican, and Christian, and his writing partner Mitch Hescox who leads the Evangelical Environmental Network (the largest evangelical group devoted to creation care). Their book, entitled Caring for Creation, provides a masterful balance of science, faith, and personal journey.

The style of the book is one I have not seen before. It is a side-by-side presentation of first science, then faith, then science, and back to faith. Interspersed within the main text are enlightening anecdotes mainly from weather forecasters across the country which show an informed lived experience of experts watching the climate change before their very eyes. Importantly the authors provide a list of concrete things that we all can do, starting right now to make a meaningful impact in reducing global warming.

Within this book there is real science. Not just about what is happening now, but the history of climate science, how we’ve known since the 1800s that human emissions of greenhouse gases like carbon dioxide can warm the atmosphere. We also hear from Douglas about observed changes to the weather we all experience. This isn’t a problem for far-off times or far-away places. This is an issue that is being manifested now.

Hescox articulates a message grounded in the proposition that the creation is a gift from God and there is a real responsibility to care for it. Not only for others distant in time and space that may suffer, but for our own good. In fact, he argues persuasively that caring for this creation can help strengthen one’s faith.

Hescox also argues from a pro-life position. Caring for creation is the ultimate pro-life stance. Squandering resources and gifts will not only cause real harm to people and our economy, but it will endanger the lives of many of the most vulnerable.

Douglas provided a great summary:

I am a scientist but I believe in absolutes – I believe in more than I can observe, measure and test. The book of Genesis tells us that God made us in his self image. He gave us big, beautiful brains and the ability to think, reason, solve problems, make smart decisions, and improve our lives. He also gave us the good sense not to foul our nest.

Both of these intertwined stories of faith and science are woven together in a way that is easily accessible for non-scientists and people who are not of faith. We don’t need to be climate scientists or religious experts to get a lot out of the authors’ perspective. 

There are a few quotes from the book that do a great job of encapsulating the central themes which I will share. 



2016 SkS Weekly Climate Change & Global Warming Digest #41

Posted on 9 October 2016 by John Hartz

Story of the Week... SkS Highlights... Toon of the Week... Quote of the Week... Graphic of the Week... SkS in the News... SkS Spotlights... Video of the Week... Coming Soon on SkS... Poster of the Week... Climate Feedback Reviews... SkS Week in Review... 97 Hours of Consensus...

Story of the Week...

A renowned economist who helped persuade the world to start taking climate change seriously has warned the global economy could “self-destruct” if countries fail to ditch fossil fuels and embrace a clean, green, high-tech future.

Professor Lord Nicholas Stern was credited with bringing about a sea change in attitudes when he calculated the cost of failing to tackle the problem in 2006. While dealing with global warming would cost one per cent of the world’s gross domestic product, doing nothing would be up to 20 times more expensive, he concluded.

Now Professor Stern, former Mexican president, Felipe Calderón, and other leading figures from politics, finance and science have launched a major new report saying Governments and businesses must change course – and quickly.

“The challenge is urgent: the investment choices we make even over the next two to three years will start to lock in for decades to come either a climate-smart, inclusive growth pathway, or a high-carbon, inefficient and unsustainable pathway,” said the report by The Global Commission on the Economy and Climate.

Global economy could 'self-destruct' if world carries on burning fossil fuels, leading economist warns by Ian Johnston, The Independent, Oct 6, 2016 

SkS Highlights...

Using the metric of comments garnered, the two most popular articles posted on SkS during the past week are:

Toon of the Week...

 2016 Toon 41



2016 SkS Weekly Climate Change & Global Warming News Roundup #41

Posted on 8 October 2016 by John Hartz

A chronological listing of the news articles posted on the Skeptical Science Facebook page during the past week.

Sun Oct 2, 2016



Pew survey: Republicans are rejecting reality on climate change

Posted on 6 October 2016 by dana1981

Climate scientists have 95% confidence that humans are the main cause of global warming over the past six decades. Their best estimate attributes 100% of global warming since 1950 to human activities90 to 100% of climate scientists and their research agree on this. Human-caused global warming is as settled as science gets.

Yet most Americans don’t realize it. Moreover, the more conservative a person’s ideology, the less likely they are to accept this scientific reality or to trust the scientific experts.

According to a new Pew Research Center poll, just 48% of Americans realize that the Earth is warming mostly due to human activity. Highlighting a vast partisan reality gap, 79% of liberal Democrats and just 15% of conservative Republicans answer the question correctly.

Science knowledge matters for Democrats, but not Republicans

Among social scientists, there’s an ongoing debate about whether facts can change peoples’ minds on scientific issues that have become politically polarized, like climate change. There’s some evidence that when conservatives have more scientific knowledge, it just gives them more tools to use in rejecting the scientific information that conflicts with their ideological beliefs.

Pew asked a variety of general science questions to test the correlation between scientific knowledge and acceptance of human-caused global warming. Overall, Democrats and Republicans got the same average score on these scientific questions, although liberal Democrats and conservative Republicans scored better than moderates in both parties. When it came to understanding that humans are causing global warming, Pew found that scientific knowledge makes a huge difference among Democrats, and no difference among Republicans.


However, previous research has shown that conservatives with climate-specific knowledge are more likely to accept climate realities.

For Democrats, ideology isn’t a factor because the main solutions to the problem (e.g. regulations and pollution taxes) don’t conflict with their ideological beliefs. Thus scientific knowledge determines whether they understand that humans are causing global warming. For three-quarters of American conservatives, their ideology prevents them from accepting that reality, regardless of their scientific literacy.



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