"It is frustrating," says climate scientist Michael Mann from his office at Penn State University in the United States.
"There certainly has not been a hiatus in global warming — global warming hasn't stopped, even though you still hear those contrarian talking points," he says.
Professor Mann, the director of the university's Earth System Science Centre, is famous for his 'hockey stick' graph that reconstructed 1,000 years of global temperatures showing a dramatic spike towards the end of the 20th century.
The 'pause', also known as the 'slow down' or the 'hiatus', refers to the average rate of warming across the whole planet's surface in the last 15 years or so. The latest major report (pdf) from the United Nations Intergovernmental Panel on Climate Change said the rate of warming between 1998 and 2012 had been about 0.05°C per decade.
This rate, the report said, was "smaller than the rate calculated since 1951" which was 0.12°C per decade.
"The occurrence of the hiatus in global mean surface temperature trend during the past 15 years raises the two related questions of what has caused it and whether climate models are able to reproduce it," the report said (pdf).
This was proof enough for some commentators that computer models of the climate were wrong and that the risks of global warming may have been overblown.
Posted on 8 April 2015 by John Hartz
- Calif. continues to shatter temperature records
- Climate change attacks: Western Canada to lose 70 percent of glaciers
- Climate-change deniers are in retreat
- Climate change: no room for debate?
- Everybody needs a Climate Thing
- Global warming hiatus explained and it's not good news
- How flood insurance could drive Americans from coasts
- In parched California, innovation, like water, has limits
- The global warming 'pause' is more politics than science
- There’s an emerging right-wing divide on climate denial. Here’s what it means (and doesn’t)
- This conservative group is tired of being accused of climate denial — and is fighting back
- Washington Gov puts focus on climate goals, and less on debate
Calif. continues to shatter temperature records
The dubious records keep piling up for California, a state wracked by four years of drought brought on by a pernicious weather pattern that has kept rains at bay and exacerbated by human-induced warming. Just one week after the state measured its lowest-ever snowpack, U.S. scientists have announced that the year so far has been the warmest on record, setting expectations for a long, hot, dry year ahead.
“2015 to date has been truly astonishingly warm in California, and we're breaking almost all the temperature records there are to break,” Daniel Swain, an atmospheric science PhD student at Stanford University, said in an email.
Calif. Continues to Shatter Temperature Records by Andrea Thompson, Climate Central, Apr 8, 2015
Posted on 8 April 2015 by dana1981
The so-called 'pause' in the rate of global warming is false and distracting. It is a politically engineered excuse to avoid taking action on climate change.
Over the past 17 years, the Earth has warmed rapidly, accumulating energy at a rate equivalent to more than four atomic bomb detonations per second. That's over 2 billion atomic bombs worth of heat built up on our planet since 1998.
As discussed in a new book by one of us (Dana Nuccitelli) Climatology versus Pseudoscience, research has shown that much of the heat buildup during that time was deposited in the deep layers of the Earth's oceans, temporarily keeping it from the surface.
A new article co-authored by the other of us (Michael Mann), shows that natural ocean oscillations have recently acted to temporarily slow the warming of the Earth's surface temperatures, in combination with a relatively quiet sun, and active volcanoes.
Despite this temporary masking of some of the surface warming, 2005, 2010, and 2014 each set records for global surface temperature, and 2015 is thus far on pace to break the record once again. Such is the profound nature of human-caused global warming, that it has overcome these many short-term natural cooling influences.
Yet a purported global warming 'pause' (more aptly named the 'faux pause') is often used as an excuse by those who oppose taking action to curb climate change. For example, Republican Senator and US presidential candidate Ted Cruz recently said on American TV:
"Many of the alarmists on global warming, they've got a problem because the science doesn't back them up. In particular, satellite data demonstrate for the last 17 years, there's been zero warming."
This assertion is problematic for several reasons.
Posted on 7 April 2015 by Andy Skuce
This is a repost from the Critical Angle blog.
One of my pastimes is downloading data and playing around with it on Excel. I’m not kidding myself that doing this means anything in terms of original research, but I do find that I learn quite a lot about the particularities of the data and about the science in general by doing some simple calculations and graphing the numbers. There’s even occasionally a small feeling of discovery, a bit like the kind that you experience when you follow a well-trodden path in the mountains for the first time:
We were not pioneers ourselves, but we journeyed over old trails that were new to us, and with hearts open. Who shall distinguish? J. Monroe Thorington
Anyway, I downloaded some historical emissions data from the CDIAC site and played around with it. To repeat, there’s nothing new to science here, but there were a few things that I found that were new to me. First, let’s look at historical emissions of CO2 from man-made sources from 1850 to 2010. Note that for all of these graphs there are no data shown for 2011-2015.
What immediately struck me—something I hadn’t fully appreciated before—was how small oil consumption was before 1950. Both world wars were carried out without huge increases in oil use, despite the massive mobilizations of armies, navies and air forces. You can make out some downward blips in coal consumption for the Great Depression (~1930) and around the end of WW2 (~1945).
It wasn’t until after 1950 that fossil-fuel consumption went nuts. Some people have taken to calling this inflection point The Great Acceleration, there’s more on this later.
What do these emissions from different sources look like as a proportion of all human emissions over this time period?
Posted on 6 April 2015 by dana1981
In 1990, University of Alabama at Huntsville scientists Roy Spencer and John Christy created a data set that estimates the temperature of the Earth’s atmosphere by using instruments on satellites (microwave sounding units) that measure microwave radiation in the atmosphere. According to their latestestimates, the Earth’s lower atmosphere has warmed significantly since satellite measurements began in 1979, but not quite as fast as thermometer measurements of temperatures at the Earth’s surface.
Spencer and Christy have also long disputed the degree to which humans are contributing to that warming, and have thus often been called to testify before Congress by policymakers seeking justification to oppose climate legislation. On the 25th anniversary of their satellite data set, Alabama.com interviewed the pairto discuss their science and climate contrarianism. The resulting discussion was quite revealing.
Posted on 5 April 2015 by John Hartz
Rob Painting's Sea Level Rise is Spiking Sharply drew the highest number of comments of the articles posted on SkS during the past week. Attracting the second highest number of comments was Dana's Global warming and drought are turning the Golden State brown.
Toon of the Week
Posted on 4 April 2015 by John Hartz
- Antarctica’s record high temp bodes ill for ice
- California Tuolumne snowpack 40 percent of worst year
- Catholics prep for Pope Francis to tackle climate in upcoming encyclical.
- Climate scientist: No, my study is not a "Death blow to global warming hysteria"
- Climate sensitivity is unlikely to be less than 2C, say scientists
- One image that shows future of climate models
- Typhoons are starting early this season, and a big one is headed toward the Philippines
- U.S. commits to slashing emissions up to 28 percent by 2025
- U.S. to commit to 28 percent emissions cut as contribution to climate treaty
- Why Corporate America is reluctant to take a stand on climate action
Antarctica’s record high temp bodes ill for ice
The Antarctic Peninsula is one of the fastest warming spots on the planet, but in recent days, a stubborn weather pattern sent temperatures skyrocketing there, setting a record high for the continent.
While the event that set the mercury soaring — called a Chinook, or foehn wind — isn’t unusual for the region, it does seem to be increasing with climate change, as winds around Antarctica become stronger. Scientists are worried that if these sudden warming events become more common or more intense, they could put the already threatened ice of the peninsula in an even more precarious situation, with serious implications for global sea level rise.
The peninsula of Antarctica is a slender arm of land that reaches out from the continent toward South America. It has warmed by about 5°F in the past 50 years, while the globe as a whole has warmed about 1.3°F.
Antarctica’s Record High Temp Bodes Ill for Ice by Andrea Thompson, Climate Central, Apr 1, 2015
Posted on 3 April 2015 by Guest Author
Today’s Australians are, by far, the best educated cohort in our history –- on paper, anyway -– but this is not reflected in the quality of our political discourse. We appear to be lacking in courage, judgement, capacity to analyse and even simple curiosity, except about immediate personal needs.
There are more than 1.1 million university students, both undergraduate and postgraduate (about 900,000 of them locals), currently at Australian universities.
Australia also has about 4.5 million graduates (nearly 20% of the population), far more than the total numbers of traditional blue collar workers. Members of trade unions amount to about one million people: 18% of the total work force and about 12% of the private sector.
Inevitably, these numbers will shift our political culture, but the process is occurring slowly.
Australia, like the US, UK, Canada and much of Europe, has undergone a serious decline in the quality of debate on public policy. The British journalist Robert Fisk has called this “the infantilisation of debate”.
In the era of “spin”, when a complex issue is involved, leaders do not explain. They find a mantra (“stop the boats!”) and repeat it endlessly, “staying on message”, without explanation or qualification. The word “because” seems to have fallen out of the political lexicon.
Evidence-based policies and actions should be a central principle in the working of our system and reliance on populism and sloganeering should be rejected, but in reality they are not.
Posted on 2 April 2015 by Guest Author
This is a re-post from Roz Pidcock at Carbon Brief
Does the fact that surface temperatures are rising slower than in previous decades mean scientists have overestimated how sensitive the Earth's climate is to greenhouse gases?
Using temperature data up to 2011, the authors work out a value of climate sensitivity of 2.5C, comfortably within the range where scientists have suggested the 'real' value lies.
Questions about climate sensitivity are complicated, and won't be solved by any single bit of research. But the new paper seems to contribute to a growing confidence among scientists that climate sensitivity is unlikely to be less than 2C.
A lower limit
Equilibrium climate sensitivity (ECS) is the warming we can expect per doubling of atmospheric carbon dioxide above pre-industrial levels. In 2013, the Intergovernmental Panel on Climate Change (IPCC) estimated the value is likely to lie between 1.5 and 4.5C. This marked a change from previous reports, which put the lower boundary at 2C.
The new paper says lowering of the limit was partly "an effect of considering observations over the warming hiatus". This refers to the last 15 years or so in which surface temperatures have risen slower than in past decades, even though we're emitting greenhouse gases faster.
Posted on 1 April 2015 by John Hartz
- Anthropocene raises risks of Earth without democracy and without us
- Australia's climate change policy on course for 'disastrous' 4C warming
- Blue Crabs migrate north as ocean warms
- BP’s extreme climate forecast puts energy giant in a bind
- California drought goes from bad to worse as state grapples with heat wave
- California drought: Sierra Nevada snowpack hits historic low
- California imposes first-ever water restrictions to deal with drought
- Carbon capture and storage: Can the UK hit climate goals without killing off heavy industry?
- Category 5 Super Typhoon Maysak sets record in Western Pacific
- Climate change threatens to kill off more Aspen forests by 2050s
- Global warming and drought are turning the Golden State brown
- Limiting climate change could have huge economic benefits, study finds
- Oceans might take 1,000 years to recover from climate change
- The hotly contested link between science denial and conspiracy theories
- US to submit plans to fight global warming; most others delay
Anthropocene raises risks of Earth without democracy and without us
This article is part of a series on Biosphere and Energy for the Democracy Futuresproject, a joint global initiative with the Sydney Democracy Network. The project aims to stimulate fresh thinking about the many challenges facing democracies in the 21st century.
Anthropocene raises risks of Earth without democracy and without us byRobyn Eckersley, The Conversation, Mar 31, 2015