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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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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 warming and drought are turning the Golden State brown

Posted on 30 March 2015 by dana1981

There’s a rapidly growing body of scientific research finding that California is in the midst of its worst drought in over a millennium, global warming has made the drought worse, and decades-long mega-droughts could become the norm in the state later this century. A new study published in the Proceedings of the National Academy of Science (PNAS) by scientists at Stanford University adds to this bleak picture for the Golden State.

There has been some confusion about the human contribution to California’s drought, now entering its fourth consecutive year, because some reports have said that humans have not influenced the amount of precipitation falling in the state thus far. This is a subject of debate – some studies have found evidence of a human ‘fingerprint’ in the high pressure ridge that’s diverted storms away from California over the past three years. But overall, while precipitation has been low, there have been a few years in the historical record where it was lower.

However, evidence indicates that California is in the midst of its worst drought in over 1,200 years. The new PNAS paper helps reconcile these two facts. As an accompanying commentary by Michael Mann and Peter Gleick notes,

Part of the challenge is that the term “drought” can be defined in different ways: for example, meteorological, hydrological, agricultural, and socioeconomic drought. Drought, most simply defined, is the mismatch between the amounts of water nature provides and the amounts of water that humans and the environment demand.

California’s worst droughts have historically happened in years that are both dry and hot. While humans may or may not be influencing the amount of rain falling in the state, we are indisputably making it hotter. If we could flip coins representing precipitation and temperature each year, the first could come up wet or dry, but humans are weighting the second such that it will increasingly come up hot. This will make conditions like those that caused California’s current record-breaking drought return more often as the planet keeps warming.

California temperature (°F) and precipitation (inches) anomalies from January 1895 to November 2014, plotted as 3-year anomalies relative to 1901–2000 mean. Data from the National Climatic Data Center nClimDiv dataset.  Source: PNAS; Mann & Gleick (2015).



2015 SkS Weekly Digest #13

Posted on 29 March 2015 by John Hartz

SkS Highlights

MarkR's New measurements confirm extra heating from our carbon dioxide garnered the highest number of comments among the articles posted on SkS during the past week. John Abraham's One satellite data set is underestimating global warming attracted the second highest and John Mason's The UK winter of 2014-15: another Tabloid FAIL the third. 

Blog Posts of Note

I won't go over every mistake Richard (Tol) has made, while flailing about looking for his "something wrong". Many of them have been well documented already. In addition to Friday's HW article, there are more demolitions at HotWhopper (here and here and here and here), at SkepticalScience (here), in a booklet by John Cook and colleagues (here) and in a rebuttal paper to Richard Tol (here) as well as an article in The Guardian by Dana Nuccitelli (here).

The fall and fall of Gish galloping Richard Tol's smear campaign by by Sou, HotWhopper, Mar 29, 2015

Richard Tol has another article about how claims of a scientific consensus don’t stand up (you can read it here if you really want to). It’s the standard message that he’s been promoting for quite some time now and I really can’t bring myself to point out the flaws again; it’s just getting tedious. I’m also tired of always being a critic. I thought I might, instead, try to write something a bit more positive. 

Persistence!, and Then There's Physics, Mar 26, 2015

Richard (Tol) is obsessed with the study by John Cook et al, which determined that almost all scientific papers on climate science, which attributed a cause to global warming, attributed it to human activity. Now anyone who's kept up with climate science knows that's a no-brainer. There is no doubt that the current global warming is caused by us. Richard himself doesn't doubt it.

Deconstructing the 97% self-destructed Richard Tol by Sou, HotWhopper, Mar 27, 2015 

Toon of the Week

2015 SkS Toon 13 



2015 SkS Weekly News Roundup #13B

Posted on 28 March 2015 by John Hartz

Earth Hour: 4 things to know about the annual evironmental event

Hundreds of millions of homes and businesses around the world will go dark Saturday night as part of Earth Hour, an annual event meant to raise awareness about climate change and the environment.

Now in its ninth year, Earth Hour encourages individuals and organizations around the world to turn off all of their non-essential lights for one hour. This year, it’s scheduled to start at 8:30 p.m. local time on Saturday, March 28.

Organizers say Earth Hour has become the world’s largest grassroots movement in support of the environment, and it has continued to grow with each passing year. More than 7,000 cities and towns in 162 countries and territories took part in Earth Hour in 2014. This year, the group behind the campaign says 172 countries are expected to take part. 

Whether you’ve participated in Earth Hour before or are thinking about taking part for the first time, here are a few things to know about it.

Earth Hour: 4 things to know about the annual evironmental event, CBC News, Mar 23, 2015



Ipso proves impotent at curbing the Mail's climate misinformation

Posted on 27 March 2015 by dana1981

David Rose is a writer for the UK tabloid Mail on Sunday, and is known for his inaccurate and misleading climate change coverage. Rose is particularly fond of cherry picking data to hide the rapid decline in Arctic sea ice. In August 2014, he published a piece focusing on the fact that at the time, there was more sea ice in the Arctic than during the record-breaking summer of 2012. Rose’s misguided focus on noisy short-term data is underscored by the new record low winter Arctic sea ice extent we experienced this year, less than seven months after his piece was published.

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