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?
Posted on 23 May 2013 by John Hartz
- Can climate-friendly development survive a fossil fuel boom?
- Climate warnings, growing louder
- Fresh water “more precious than gold” in Bangladesh
- Heartland Institute wastes real scientists' time – yet again
- Heat-related deaths in Manhattan projected to rise
- How bad is the rebound from energy efficiency efforts?
- No matter how strong the evidence, deniers will keep denying
- Stressed ecosystems leaving humanity high and dry
- The Canadian "War on Science"
- Understanding storms and global warming
- Who’s escaping climate change ‘mire and muck’?
- Who's paying the price for global warming?
Can climate-friendly development survive a fossil fuel boom?
The planes from Johannesburg to Mozambique's airports of Maputo, Tete and Pemba are full of business people these days. My neighbours on the flight from South Africa last week were not heading to Mozambique's beautiful resorts but there to take up the opportunities from the oil, gas and coal revolution that is transforming parts of the country and potentially the entire economy.
Can climate-friendly development survive a fossil fuel boom? by Sam Bickersteth, Chief Executive, CDKN, AlertNet, May 21, 2013
Posted on 23 May 2013 by dana1981
In an opinion article for the London Times this past Monday, writer Matt Ridley discussed his interpretation of a new paper which suggests that the Earth's climate sensitivity may be a bit lower than current best estimates. Climate sensitivity refers to the average amount of warming that will occur at the Earth's surface in response to an increased greenhouse effect.
This new paper, led by Alexander Otto at the University of Oxford, suggested that the Earth's surface may warm a bit more slowly than climate models generally indicate. I roughly estimate that about 80% of the warming over the past century would be due to human carbon dioxide emissions, if the results of this study are correct. The good news is that Ridley has accepted the consensus amongst 97% of climate experts that humans are causing global warming and has moved on to examine the consequences.
"...our new findings mean that the changes we had previously expected between now and 2050 might take until 2065 to materialise instead."
Posted on 23 May 2013 by John Cook
After our Consensus paper was published with extensive media coverage, law professor and climate communicator Dan Kahan posted an emotive blog post (he characterised it as a "haughty outburst"). He questioned the value of a study measuring consensus and whether consensus is something climate communicators should be emphasising.
Once Dan had a chance to calm down, we corresponded about his post and he suggested he summarise his views in a 4-point article that I could respond to. Dan's 4 point critique of Cook et al. and my response have now been posted on his blog. He also included a response from science journalist Scott Johnson. I recommend you head over to Kahan's blog post summarising all three viewpoints, but here are a few choice excerpts.
A Rough Guide to the Jet Stream: what it is, how it works and how it is responding to enhanced Arctic warming
Posted on 22 May 2013 by John Mason
Barely a week goes by these days in the Northern Hemisphere without the jet stream being mentioned in the news, but rarely do such news items explain in detail what it is and why it is important. As a severe weather photographer this past 10+ years, an activity which requires successful DIY forecasting, I've had to develop an appreciation into what makes it tick. This post, then, is a start-from-scratch primer based on that knowledge plus some valuable assistance from academia into where the current research is heading. Because of its length and breadth of coverage, I've broken it up into bookmarked sections for easy reference: to come back here click on 'back to contents' in each instance.
We live at the bottom of a soup of gases, constantly moving in all directions - our atmosphere. Virtually all of our tangible weather goes on in its lowest major division, the Troposphere. This division varies in average thickness from about 9000m over the poles to 17000m over the tropics - in other words, it's thinnest in cold areas and thickest in hot areas, because hot air is more expansive than cold air. Likewise it fluctuates in thickness on a seasonal basis according to whether it's warmer or colder. Above it lies the Stratosphere, while below it lies the surface of the Earth.
Posted on 21 May 2013 by John Hartz
- 10 Reasons Canada Needs to Rethink the Tar Sands
- A black mound of Canadian oil waste is rising over Detroit
- Ads aimed at U.S. lawmakers
- Could NAFTA force Keystone XL on United States?
- Is Canada’s tar sands oil too dirty for Europe?
- Keystone XL pipeline has become too big to approve
- Keystone XL pipeline not a big deal
- Lines in the sand
- Major donors urge Obama to reject Keystone XL pipeline
- Native Americans quit talks over Keystone XL pipeline
- UK signals support for EU import of Canadian tar sands oil
- US House set to approve construction of Keystone XL pipeline
- US "national interest" argument for Keystone XL weakens
10 Reasons Canada Needs to Rethink the Tar Sands
As a Canadian it blows my mind that we can have the second largest deposits of oil in the world, but our government remains billions in debt and one in seven Canadian children live in poverty.
I feel like we are being played for fools here in Canada, because foreign owned oil companies like ExxonMobil, British Petroluem and PetroChina (71% of oil sands production is owned by foreign shareholders) are making billions exporting raw tar sand from our country, while us citizens are dealing with all the nasty downsides.
Time for a tar sands reality check.
10 Reasons Canada Needs to Rethink the Tar Sands by Kevin Grandia, De Smog Canada, May 16, 2013
Posted on 21 May 2013 by Kevin C
Climate scientists have traditionally looked at climate over long periods - 30 years or more. However the media obsession with short term trends has focussed attention on the past 15-16 years. Short term trends are much more complex because they can be affected by many factors which cancel out over longer periods. In a recent interview James Hansen noted "If you look over a 30-40 year period the expected warming is two-tenths of a degree per decade, but that doesn't mean each decade is going to warm two-tenths of a degree: there is too much natural variability".
Over the winter vacation we produced a video which tried to explain the contributions to the recent temperature trend based on the best evidence available at the time, however the rapid pace of development in this area has thrown significant doubt on the conclusions. While the video has significant educational content, the conclusions do not reflect a scientific consensus, so we will be withdrawing it and will work on an updated version.
The video was based on an approach pioneered by Lean and Rind (2008) and Foster and Rahmstorf (2011), by determining the contribution of known influences on global temperature to best explain those temperatures. However this approach can give misleading results if significant influences on temperature are missing from the analysis, or if wrong influences are included. Therefore we need a comprehensive list of possible factors which might affect the short term trend. Based on the latest literature, the following should be considered:
Posted on 20 May 2013 by Matt Birdoff
Over the last few days, there has been intense interest in our consensus paper and The Consensus Project website. The fact that the paper has been reported widely in mainstream media across the world is an important step towards reducing the gaping chasm between public perception of scientific consensus and the 97% reality. Having President Obama tweet about our paper to over 31 million followers (with 2,400+ retweets!) will certainly help close the consensus gap.
However, as the above Consensus Gap graph shows, it will take a broad, persistent effort to reduce this misperception. To contribute to this effort, our team at SJI Associates (who put together the amazing Consensus Project website) will continue to work on eye-grabbing, compelling graphics. These graphics are designed to be shared through social media - on Facebook, Twitter, etc.
Posted on 19 May 2013 by John Hartz
On May 15, the peer-reviewed paper, Quantifying the consensus on anthropogenic global warming in the scientific literature was published in the scientific journal, Environmental Research Letters. The paper presents The Consensus Project (TCP) – a survey of over 12,000 peer-reviewed climate science papers by our volunteer, citizen science team at Skeptical Science. The analysis found a 97% consensus among papers taking a position on the cause of global warming in the peer-reviewed literature that humans are responsible.
Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature by Dana & John Cook generated a much discussion with some readers challenging the validity of the results of the newly published TCP. John Cook's Measure the climate consensus yourself with our Interactive Rating System and John Hartz's 2013 SkS News Bulletin #12: The Consensus Project rounded out the posts devoted to the TCP.
As discussed below, the paper generated an immense amount of media coverage. There is also a website, Facebook page, and Twitter account associated with TCP, to make it easy for people to spread the word about these important results. More details on this to come next week.
Toon of the Week
Posted on 19 May 2013 by John Hartz
- Burning tar sands = 'unsolvable' climate crisis: Hansen
- Climate change has shifted the North and South Poles
- Climate change is happening… So what?
- Fiji's villagers move uphill to escape rising seas
- Global warming has not stalled
- Go fish (somewhere else): Warming oceans are altering catches
- Ignoring the cost of climate change is bad business
- Mount Everest's ice is melting
- Profits vs. disaster in Arctic meltdown
- Warmer springs linked to dwindling snow in Rocky Mountains
- Why we know about the greenhouse gas effect
- Zombie climate sceptic theories survive
Burning tar sands = 'unsolvable' climate crisis: Hansen
Fresh off his resignation from NASA, leading climate scientist James Hansen is making the rounds this week, warning media and lawmakers that not only are we heading for a "tremendously chaotic" climate, but if we dig up and burn Canadian tar sands, the climate crisis will be rendered "unsolvable."
Burning Tar Sands = 'Unsolvable' Climate Crisis: Hansen by Jacob Chamberlain, Common Dreams, May 17, 2013
Posted on 18 May 2013 by John Hartz
Obama tweets analysis that 97% of peer-reviewed science confirms human-caused global warming by Lauremce Lewis, Daily Kos, May 16, 2013
- Climate denial's death knell
- Climate research nearly unanimous
- Consensus study
- Is the science settled?
- It's official! Humans caused global warming.
- Global warming consensus: We can haz it!
- 'Overwhelming' consensus for manmade warming
- Scientists agree (again)
- Scientists agree global warming is man-made
- Scientific 'consensus' that humans to blame
- Scientists say united on global warming
- Survey finds 97% of climate science papers agree
Climate Denial's Death Knell
A new survey conducted by a team of volunteers at Skeptical Science has definitively confirmed the scientific consensus in climate science literature -97 percent of peer-reviewed papers agree that global warming is happening and human activities are responsible.
Climate Denial's Death Knell: 97 Percent of Peer-Reviewed Science Confirms Manmade Global Warming, Consensus Overwhelming by Brendan DeMelle, DeSmog Blog, MAy 15, 2011
Posted on 17 May 2013 by John Cook
The Consensus Project was a long, ambitious effort by many volunteers, lasting 12 months from beginning to submission of our paper to peer-reviewed journal Environmental Research Letters. The project involved citizen science from start to finish - from the rating of the abstracts to the collection of scientists' emails to crowd-funding the journal fee to make the paper free to the public. It was an enormous collaborative effort that the entire Skeptical Science community contributed to. The effort has resulted in strong media interest including a tweet from President Obama.
We want our results to be transparent and replicable, so that anybody can quantify the scientific consensus on human-caused global warming for themselves. Thus we've created an interactive rating system that lets Skeptical Science readers rate the abstracts from The Consensus Project. You can then compare your ratings to the results from Quantifying The Consensus. Note that your ratings are private - no specific ratings will be publicly attributed to individuals.
All papers receive two types of ratings - the category of research and the level of endorsement of anthropogenic global warming (AGW). Here are general definitions of each category and endorsement level, although we've also provided a more detailed set of guidelines.
Skeptical Science Study Finds 97% Consensus on Human-Caused Global Warming in the Peer-Reviewed Literature
Posted on 16 May 2013 by dana1981, John Cook
A new survey of over 12,000 peer-reviewed climate science papers by our citizen science team at Skeptical Science has found a 97% consensus among papers taking a position on the cause of global warming in the peer-reviewed literature that humans are responsible.
Lead author John Cook created a short video abstract summarizing the study:
The Abstracts Survey
The first step of our approach involved expanding the original survey of the peer-reviewed scientific literature in Oreskes (2004). We performed a keyword search of peer-reviewed scientific journal publications (in the ISI Web of Science) for the terms 'global warming' and 'global climate change' between the years 1991 and 2011, which returned over 12,000 papers.
Posted on 15 May 2013 by John Hartz
- A change in temperature
- Arctic waters growing alarmingly acidic
- 'Best estimate' for impact of melting ice on sea level rise
- Canada sells out science
- Climate change 'will make hundreds of millions homeless'
- Fewer Rain Forests mean less energy
- Obama administration outlines new policy the Arctic
- Ralph Keeling ponders a sobering milestone
- Sea levels are rising - but how quickly?
- Swift political action can avert a carbon dioxide crisis
- UK government faces an exodus of energy experts
- Warmer climate threatens Africa’s vital cassava crop
A change in temperature
Since 1896, scientists have been trying to answer a deceptively simple question: What will happen to the temperature of the earth if the amount of carbon dioxide in the atmosphere doubles?
A Change in Temperature by Justin Gillis, New York Times, May 13, 2013
Posted on 15 May 2013 by Dumb Scientist
Dr. Harrison Schmitt and Dr. William Happer, who have scientific backgrounds but are not climate scientists, just wrote an opinion piece in The Wall Street Journal. Despite their claims, global warming continues. This continued warming is confirmed by GRACE, ICESat, InSAR, GPS, and camera observations of ice sheet mass loss, which absorb heat without warming as they melt. The continued warming is also confirmed by global sea ice loss, which absorbs heat without warming as it melts. The continued warming is also confirmed by increasing global ocean heat content, which absorbs heat without warming the surface... until it’s released in an El Niño.
Posted on 14 May 2013 by John Mason
During the late Pliocene and early Pleistocene Series of the Cenozoic Era, 3.6 to 2.2 Ma (million years ago), the Arctic was much warmer than it is at the present day (with summer temperatures from 3.6-3.4 Ma some 8oC warmer than today). That is a key finding of research into a lake-sediment core obtained in Eastern Siberia, which is of exceptional importance because it has provided the longest continuous late Cenozoic land-based sedimentary record thus far. The sedimentary sequence dates from recent times back to 3.6 Ma when the lake was formed by a large extraterrestrial impact. During the warm period, atmospheric carbon dioxide concentrations were close to those of today, at around 400 parts per million, indicative of a strong climate sensitivity signal in the Arctic, which has again warmed very rapidly in recent decades. The lake sediment record has thus provided us with a snapshot of how the Arctic may look in the near future.
Geologists divide geological time into Eons (the longest divisions), Eras, Systems and Series. The Pliocene (5.333-2.588 Ma) is the final Series of the Neogene System and the Pleistocene (2.588 Ma-11,700 years ago) is the first Series of the Quaternary System, both being part of the Cenozoic Era, the latest Era of the Phanerozoic Eon.
Just to get that into context, here is all of geological time plotted against the human 12-month calendar year, so that geological time starts on the first second of New Years' Day and the present is the last second of New Years' Eve. On such a scale, the whole Cenozoic Era equates to a tiny bit of late December!
Posted on 13 May 2013 by John Hartz
- Al Gore tells Obama to cancel Keystone XL
- Alberta oil sands production likely to double by 2022
- Can carbon capture clean up Canada’s oil sands?
- Canada says it may take EU to WTO over oil sands dispute
- Carbon dioxide approaching a new high
- Foes suggest a tradeoff if pipeline is approved
- House GOP prepares fast-track for Keystone XL
- Indigenous resistance grows strong
- Keeping the faith in carbon capture and storage
- Keystone XL could cost society over $100 billion per year
- Norway, Canada, the United States and the Tar Sands
- 'This Is Our Last Chance'
- U.S. decision on Keystone XL pipeline seen dragging past summer
Al Gore tells Obama to cancel Keystone XL
Love him or loath him, you can say one thing Al Gore at the moment. He is certainly winding the Canadians up into a right old rage.
Al Gore Tells Obama to Cancel KXL by Andy Rowell, Oil Change International, May 7, 2013
Posted on 13 May 2013 by dana1981
Although it is still within the range of model simulations, the rate of global surface air warming over the past decade has slowed. Climate scientists, being scientists, would like to explain exactly why that has happened.
There are several possible explanations. Perhaps it's due to the natural internal variability (short-term noise) in the climate system, with more heat being shifted to the deeper oceans as a result of more recent La Niña events. Perhaps it's due to a smaller global energy imbalance due to more aerosol cooling and lower solar activity offsetting more of the greenhouse gas-caused warming. Perhaps it's a combination of several factors, but which is the main cause of the slowed surface warming over the past decade?
Meehl et al. (2011) found that in their model simulations, there were 'hiatus decades' with little surface warming, but increased deep ocean warming (Figure 1). Similarly, Guemas et al. (2013) concluded that most of the recent slowed surface warming can be attributed to the increased accumulation of heat in the oceans.
Figure 1: Composite global linear trends for hiatus decades (red bars) and other decades (green bars). Positive values for top of the atmosphere (TOA) net radiation (left-hand side) indicate energy accumulating in the system (i.e. global warming). Right-hand side shows ocean heat content decadal trends, for the various ocean layers. From Meehl et al. (2011).
Posted on 12 May 2013 by John Hartz
KK Tung posted part 2 of his article, The anthropogenic global warming rate: Is it steady for the last 100 years?. It generated an ongoing discussion with Dr. Tung on the role of the Atlantic Multidecadal Oscillation (AMO) in global climate change.
Toon of the Week
H/T to Joe Romm's Climate Progress blog.
Posted on 11 May 2013 by dana1981
This is Peter Hadfield's (potholer's) latest climate video, summarizing the evidence for human-caused climate change, excluding climate models and the IPCC.
Posted on 11 May 2013 by John Hartz
- Are we doomed to food insecurity?
- Big Oil may destroy world's largest rain forest
- Chile looks to volcanoes and geysers for energy
- Climate milestone is a moment of symbolic significance
- Does God hate climate change?
- Fresh analysis of the pace of warming and sea-level rise
- Greenland’s ice loss may slow, but coasts still At risk
- If the Oceans die - we die
- New study tells three million-year old story of the Arctic
- No need to worry about global warming, folks
- The coming GOP civil war over climate change
- Thoreau's radicalism and the fight against the fossil-fuel industry
- What you need to know about climate sensitivity
- What's causing the surface warming slowdown?
Are we doomed to food insecurity?
Half the world's population—5.2 billion people—could be doomed to an insecure and greenhouse gas-causing reliance on food imports by 2050, according to a new study.
Are We Doomed to Food Insecurity? by Andrea Germanos, Common Dreams, May 8, 2013