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- Lessons from Past Predictions: Hansen 1981
- Two Centuries of Climate Science: part two - Hulburt to Keeling, 1931- 1965
- New research from last week 17/2012
- John Nielsen-Gammon Comments on Continued Global Warming
- 2012 SkS Weekly Digest #17
- Richard Alley on Today's CO2 Levels
- Richard Alley - We Can Afford Clean Energy
- Alberta’s bitumen sands: “negligible” climate effects, or the “biggest carbon bomb on the planet”?
- Lessons from Past Predictions: Vinnikov on Arctic Sea Ice
- ABC documentary demonstrates the how and why of climate denial
- Two Centuries of Climate Science: part one - Fourier to Arrhenius, 1820-1930
- Levitus et al. Find Global Warming Continues to Heat the Oceans
- New research from last week 16/2012
- Global Warming Causing Heat Fatalities
- 2012 SkS Weekly Digest #16
- Climate Change Boosts Then Quickly Stunts Plants, Decade-long Study Shows
- Weird Winter - March Madness
- Why Are We Sure We're Right? #1
- Global Surface Warming Since 1995
- GISTEMP: Cool or Uncool?
- First Look at HadCRUT4
- New research from last week 15/2012
- Cliff Ollier: Swimming In A Sea of Misinformation
- 2012 SkS Weekly Digest #15
- Which plants will survive droughts, climate change?
- Global Warming in a Nutshell
- Why David Archibald is wrong about solar cycles driving sea levels (Part 1B)
- Linking Weird Weather to Rapid Warming of the Arctic
- NASA Climate 'Skeptics' Respond with Science! Just Kidding.
- Data Contradicts Connection Between Earth's Tilt and the Seasons
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 refutes 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?
Lessons from Past Predictions: Hansen 1981
Posted on 3 May 2012 by dana1981
In previous Lessons from Past Predictions entries we examined Hansen et al.'s 1988 global warming projections (here and here). However, James Hansen was also the lead author on a previous study from the NASA Goddard Institute for Space Studies (GISS) projecting global warming in 1981, which readers may have surmised from my SkS ID, is as old as I am. This ancient projection was made back when climate science and global climate models were still in their relative infancy, and before global warming had really begun to kick in (Figure 1).
Figure 1: Annual global average surface temperatures from the current NASA GISS record through 1981
As Hansen et al. described it,
Two Centuries of Climate Science: part two - Hulburt to Keeling, 1931- 1965
Posted on 2 May 2012 by John Mason
The fact that carbon dioxide is a 'greenhouse gas' - a gas that prevents a certain amount of heat radiation escaping back to space and thus maintains a generally warm climate on Earth, goes back to an idea that was first conceived, though not specifically with respect to CO2, nearly 200 years ago. The three-part tale of how this important physical property, its role in the geological past and understanding how it may affect our future, covers about two centuries of enquiry, discovery, innovation and problem-solving.
above: atmospheric carbon dioxide levels from the late 1950s onwards. The red wiggles mark out seasonal variations in uptake by plants.
We resume this narrative in 1931, when American physicist E.O Hulburt ran calculations to determine the effect of doubling carbon dioxide once again, and, including the added burden of water vapour, he came up with a figure of around 4°C of warming. He also rebutted Ångström's work and determined that, regardless of convective processes, it was the escape of infra-red radiation to Space (or the hinderance thereof) that was of key importance. The resultant paper appeared in a the journal Physical Review, which tended not to be read by earth and atmospheric scientists and was as a consequence missed by many of them. In any case, it was generally thought that Earth's climate system maintained itself in some natural kind of balance. In retrospect, given the dramatic climate changes that had led to the ice-ages, this was a curious stance to take.
Seven years later, English engineer Guy Callendar, something of an outsider (a steam-engine specialist but with a very keen interest in meteorology), revived the idea, having discovered evidence of a warming temperature trend in the early twentieth century from compilations of temperature records. At long last, the actual levels of carbon dioxide in the atmosphere were revisited: Callendar found they had increased by some 10%, which he suggested may have caused the warming, and he went on to add that over the coming centuries there could be a climate shift to a permanently warmer state.
New research from last week 17/2012
Posted on 1 May 2012 by Ari Jokimäki
Is it something that is happening in the Sun,
or are atmospheric GHG's the smoking gun?
Temperature is rising on the surface of the sea.
Did we do it, or did nature do it for free?
Cryospheric presence in Arctic is very nice.
After mankind's tricks, does anybody see there any ice?
What causes changes in avalanches of snow,
or in floods, does anyone know?
When wetlands are all gone, rotten and stink,
what can carbon do after that, where does it sink?
Migration is something that trees and butterflies have to face.
I just wonder if they'll end up in same place?
The move from MWP to LIA is a big change,
but weather can do it with same regime, isn't that strange?
Subtropical clouds are difficult things to simulate.
Can't climate models ever do it, or is it their fate?
John Nielsen-Gammon Comments on Continued Global Warming
Posted on 1 May 2012 by dana1981
John Nielsen-Gammon, Texas State Climatologist and a Professor of Atmospheric Sciences at Texas A&M University, has a nice article published in the Houston Chronicle regarding the misconception that global warming has stopped based on global surface temperatures.
"It’s common knowledge among those who follow such things that global temperatures have not gone up very much in the past several years. This has caused many to believe that the recent lack of warming contradicts what climate models say should happen in response to the increasing Tyndall gases. This, in turn, has provoked the counterargument that the Earth is still warming, just on a longer time scale, or that the recent period is too short to yield statistically significant results."
Nielsen-Gammon goes on to perform a simple analysis of the global surface temperature data, categorizing each year as an El Niño, La Niña, or El Niño Southern Oscillation (ENSO)-neutral year.
"I decided to take a simple approach at looking at the effect of ENSO. Using GISTemp Land/Ocean Index values and Niño 3.4 values, I computed 12-month running averages of Niño 3.4 and compared them to the average GISTemp values at lags of 0, 3, and 6 months. Foster and [Rahmstorf] used a [different] ENSO index and found optimal lags between 2 and 5 months. So one would guess that a 3-month lag would fit the data best in my case, and indeed it did.
The normal threshold for El Niño or La Niña, as applied by the Climate Prediction Center, is for five consecutive months of at least 0.5 C above or below normal in a key region of the tropical Pacific. For working with annual data, I decided to call an annual average above 0.5 C an El Niño and an annual average below -0.5 C a La Niña. Then I plotted it up, color-coding each year for whether it was El Niño, La Niña, or neither (neutral). Here’s the result:"
2012 SkS Weekly Digest #17
Posted on 30 April 2012 by John Hartz
SkS Highlights
Dana's Global Warming Causing Heat Fatalities garnered a goodly number of heated comments by SkS readers and authors this past week. John Cook's ABC documentary demonstrates the how and why of climate denial drew the second highest number of comments. A "must see" video of Naomi Oreskes is embedded in it. Levitus et al. Find Global Warming Continues to Heat the Oceans by Dana rounded out the top three comment generators of the week.
Toon of the Week
Source: Royalty Free Cartoons
Richard Alley on Today's CO2 Levels
Posted on 30 April 2012 by dana1981
Another re-post from Climate Crocks - videos from Earth, the Operator's Manual and Peter Sinclair featuring Richard Alley discussing today's high CO2 levels.
Richard Alley - We Can Afford Clean Energy
Posted on 29 April 2012 by dana1981
Re-posted from Climate Crocks, an excellent video showing Richard Alley debunking the myths Renewable energy is too expensive and CO2 is not a pollutant in one fell swoop. This video is well worth watching:
Alberta’s bitumen sands: “negligible” climate effects, or the “biggest carbon bomb on the planet”?
Posted on 28 April 2012 by Andy S
*The climate effects of bitumen development are significant once viewed in the perspective of probable emissions over the rest of this century.
*The climate impact of coal consumption is greater than that of bitumen, particularly when non-mineable coal is considered.
*Accelerated expansion of bitumen extraction will make climate mitigation efforts much more difficult.
*Because of its high carbon emissions and high extraction costs, further bitumen development would not be viable if stringent global emissions policies were adopted.
The accelerating development of the huge bitumen* resources in Alberta has produced a great deal of recent public interest, due mainly to controversial proposals to build two big new pipelines: one connecting Alberta to the US Gulf Coast (Keystone XL) and the other to the Pacific coast of British Columbia (Northern Gateway). Much of the discussion has revolved around the dangers of leaks from the pipelines themselves and, in the case of the Northern Gateway proposal, the risks of tanker accidents in the narrow fjords of BC’s pristine northern coast and the turbulent Hecate Strait. Recent publications have also drawn attention to the massive damage to peatlands caused by bitumen mines and to the pollution of the Athabasca River. However, for the purposes of this article, I will focus only on the effect of bitumen sand exploitation on climate change.
The general topic was discussed previously at Skeptical Science in Tar Sands Impact on Climate Change.
Lessons from Past Predictions: Vinnikov on Arctic Sea Ice
Posted on 27 April 2012 by dana1981
We previously did a Lessons from Past Predictions entry on year-to-year Arctic sea ice extent predictions. However, we were recently alerted to an interesting longer-term Arctic sea ice prediction published in Science by Vinnikov et al. (1999). This study used climate models from the Geophysical Fluid Dynamics Laboratory (GFDL) and Hadley Centre, forced by greenhouse gases and sulfate aerosols. The authors used these models to hindcast past Arctic sea ice extent measurements and predict future changes. Regarding observational data up to 1999, Vinnikov et al. noted:
"the observed decrease in Northern Hemisphere sea ice extent agrees with the transient simulations, and both trends are much larger than would be expected from natural climate variations."
This post will focus primarily on the projections of future Arctic sea ice extent decline in Vinnikov et al. (Figure 1). As we'll see, Vinnikov significantly under-predicted the Arctic sea ice death spiral, which is over 99.9% likely to be influenced by human-caused global warming.
ABC documentary demonstrates the how and why of climate denial
Posted on 26 April 2012 by John Cook
Tonight, the Australian TV channel ABC will air the documentary I Can Change Your Mind about Climate. The show features climate activist Anna Rose and retired Liberal senator Nick Minchin attempting to change each others' minds about climate change, by introducing each other to a number of leading voices on climate change. Some have argued, with a fair amount of justification, that its unwise to give the small minority of those who reject climate science an equal voice with the overwhelming majority of climate scientists who agree that humans are causing global warming. However, in an article published today at ABC Environment, I argue (in a valiant effort to take a glass-half-full approach) that this documentary can instruct us on the how and why of climate denial. Here's an excerpt:
What do you do if all the world's experts disagree with you? A decades old technique perfected by the tobacco industry is to manufacture the appearance of a continued debate through fake experts. Climate change is a complicated, multi-disciplinary science and yet many of the leading voices who purport to know better than the experts have never published a single piece of climate research. Of Nick's four voices against the scientific consensus, we have a blogger, an engineer and a political lobbyist. Nick turns to only one actual climate scientist, whose research has been thoroughly refuted in the peer-reviewed literature.
Alternatively, when the world's leading experts disagree with you, another popular approach is to don a tinfoil hat and cry conspiracy. A small minority seem to believe that tens of thousands of climate scientists across the globe are all engaged in a conspiracy. Of course there is no evidence for this (which to the paranoid is further proof of a conspiracy), even when scientists' emails are stolen and pored over with a fine-tooth comb. Fortunately very little tin-foil-hattery is in evidence throughout the documentary, apart from a throwaway line from David Evans that scientists are 'concealing the evidence'.
How does one deny the consensus of evidence? One straightforward approach is to simply ignore it! Jo Nova ignores satellite observations that directly measure an increased greenhouse effect when she claims the warming effect from carbon dioxide (CO2) is immeasurable. Richard Lindzen claims negative feedbacks will cancel out CO2 warming, citing the Earth's past. But it's precisely the Earth's past that provides many independent lines of evidence for reinforcing feedbacks that are an integral part of our climate system.
Marc Morano delivers a breathtaking torrent of misinformation (although I'm not sure he did take a breath) that ignores entire swathes of evidence. He overlooks the fact that Arctic sea ice has dramatically thinned with the total amount of ice hitting record low levels in 2011. He ignores that global warming is still happening, with our planet currently absorbing heat at a rate of two Hiroshima bombs per second. Genuine scepticism requires considering the full body of evidence in order to properly understand what's happening to our climate. What we witness from Nick Minchin's witnesses is not genuine scepticism but rejection of any inconvenient evidence.
Observing the misinformation of David Evans, Jo Nova, Marc Morano and Richard Lindzen is an examination into the how of climate denial, exposing the techniques common to all movements that deny a scientific consensus. To explain the why, I leave it to Naomi Oreskes who deconstructs Nick Minchin's rejection of climate science in some powerful footage that tragically didn't make it into the final cut. Thanks to the magic of the interweb, here it is in all its YouTube glory (many thanks to the producers for granting permission for me to upload the video):
Two Centuries of Climate Science: part one - Fourier to Arrhenius, 1820-1930
Posted on 26 April 2012 by John Mason
The fact that carbon dioxide is a 'greenhouse gas' - a gas that prevents a certain amount of heat radiation escaping back to space and thus maintains a generally warm climate on Earth, goes back to an idea that was first conceived, though not specifically with respect to CO2, nearly 200 years ago. The three-part tale of how this important physical property, its role in the geological past and understanding how it may affect our future, covers about two centuries of enquiry, discovery, innovation and problem-solving.
To pick up the scientific trail of what is today known as the Greenhouse Effect, we need to travel back in time to France in the 1820s. Napoleon, defeated at the Battle of Waterloo just a few years previously, had just died, but somebody who had at one time undertaken significant engineering and academic projects for the late Emperor was now busily engaged on his investigations of the physical world, with a specific interest in the behaviour of heat. This was Jean Baptiste Joseph Fourier (1768–1830).
Fourier had calculated that a planetary object the size of Earth should, quite simply, not be as warm as it is at its distance from the Sun. Therefore, he reasoned, there must be something else apart from incoming solar radiation, some other factor that keeps the planet warmer. One suggestion he came up with was that the energy coming in from the sun in the form of visible and ultra-violet light (known back then as "luminous heat") was easily able to pass through Earth's atmosphere and heat up the planet's surface, but that the "non-luminous heat" (now known as infra-red radiation) then emitted by the Earth's surface could not make it back in the opposite direction quite so readily. The warmed air must, he reasoned, act as some kind of insulating blanket. That was about as far as he got with the idea back then, as the detailed measurements required to explore this hypothesis were not available, given the technology of the day.
above: the Grandfathers of Climate Science
Levitus et al. Find Global Warming Continues to Heat the Oceans
Posted on 25 April 2012 by dana1981
Levitus et al. had previously published updated ocean heat content (OHC) data on the National Oceanic Data Center (NODC) website, labeled as "Levitus et al. in preparation" (Figure 1).
Figure 1: Global OHC for the upper 2000 meters of oceans (NODC)
Levitus et al. (2012) is now in press, discussing the OHC data published by NODC. Figure 2 below (from Levitus et al.) presents the data in a similar fashion to Figure 1 above, but breaks out the data to show the OHC contribution from the 700 to 2000 meter ocean layer.
New research from last week 16/2012
Posted on 24 April 2012 by Ari Jokimäki
I'm sick and tired of coming up something witty and funny week after week for these introductions, so now I'll just write this boring summary: Themes of this week are mapping, Arctic sea ice, non-Arctic air traffic, greenhouse gases (which by the way has nothing to do with gardener's stomach problems), paleoclimate, biosphere, groundwater, seawater, groundweather, seaweather, and what else? Oh yes, and climate, of course. All this in just 15 little studies plus one classic.
Global Warming Causing Heat Fatalities
Posted on 24 April 2012 by dana1981
One of the fallback positions of climate denial after the assertions that "It's not happening" and "It's not us" fail is "It's not bad." The latest incarnation of this myth courtesy of Pat Michaels' serial data deletion colleague Chip Knappenberger argues that those who seek to mitigate global warming are actually endangering public health because, and believe it or not this is a direct quote:
"“longer, more intense and more frequent heat waves” may actually improve the public health and welfare"
Here is the specific argument Knappenberger makes in attempting to defend this seemingly absurd thesis:
"more frequent exposure to heat waves will lead the population to adapt to them, better preparing them for their occurrence, and ultimately reducing the rate of mortality and morbidity."
By this logic gang violence is great because it makes people more adept at dodging bullets.
2012 SkS Weekly Digest #16
Posted on 23 April 2012 by John Hartz
Happy Earth Day!
SkS recommends an interview with James Powell by Big Think - James Lawrence Powell: Grandpa, What Did You Do on Earth Day, 2012?
SkS Highlights
By design, Rob Honeycutt's Why Are We Sure We're Right? #1 generated a considerable amount of intense discussion between SkS readers and authors. In this first part of a two-part post, three SkS authors (Dikran Marsupial, Glenn Tamblyn, and Ari Jokimäki) answered the following questions posed by Honeycutt:
-
Why am I sure I'm right?
-
How does anyone reading my words differentiate between what I'm saying and what someone else denying climate change is saying?
Toon of the Week
Climate Change Boosts Then Quickly Stunts Plants, Decade-long Study Shows
Posted on 23 April 2012 by John Hartz
This is a reprint of a press release posted by the National Science Foundation (NSF) on April 10, 2012.
Global warming may initially make the grass greener, but not for long
Composite of the ecosystems studied, arranged left to right in order of increasing elevation. |
Global warming may initially make the grass greener, but not for long, according to new research results.
Weird Winter - March Madness
Posted on 22 April 2012 by Rob Honeycutt, grypo
Here's the latest video creation from Peter Sinclair and Climate Denial Crock of the Week. In my own opinion this is one of the strongest videos Sinclair has produced yet. In this episode we are treated to interviews with Dr. Jeff Masters from Weather Underground, Paul Douglas from Weathernation TV, Stu Ostro from the Weather Channel, Scott Mandia professor of Physical Sciences, and Dr Kevin Trenberth from NCAR.
This video does a great job of explaining the how and why of the recent March heat wave in the US.
In Part II of "Weird Winter", several scientists discuss the recent research that links the decreasing Arctic sea ice to changing jet streams which causes profound effects on mid-latitute weather in the Northern Hemisphere. Last week, SkS reposted Jennifer Francis' Yale essay on her work and its implications.
Why Are We Sure We're Right? #1
Posted on 21 April 2012 by Rob Honeycutt
This question struck me while reading a climate change denial website not long ago. The language being used, I thought, seemed eerily similar to language I read on pro-AGW sites. It seemed like a reasonable - and skeptical - notion to explore the idea of why I believe I'm correct when I'm out there on the internet confidently pounding the table over the immediacy of this issue. Why am I sure I'm right? How does anyone reading my words differentiate between what I'm saying and what someone else denying climate change is saying?
I posed this question to the authors at Skeptical Science and the responses have been varied, insightful and engaging. The question itself is provocative and I believe will lead to lots of opinions and discussion.
What I'm going to do is post the responses of several of the SkS authors here and see where the discussion leads us.
First is Dikran Marsupial:
Global Surface Warming Since 1995
Posted on 20 April 2012 by dana1981
Santer et al. (2011) examined modeled vs. observed trends in the temperature of the lower troposphere (TLT) and found that climate "skeptics" generally exaggerate the discrepancy between the two. Nevertheless, based on University of Alabama at Huntsville (UAH) and Remote Sensing Systems (RSS) data, TLT is not warming as quickly as models expect. That being said, we don't know if the discrepancy is due to models overestimating TLT, UAH and RSS underestimating it (which is a very plausible possibility), or both.
One key finding from Santer et al. is that we must examine at least 17 years of TLT data to discern a human influence on tropospheric temperatures:
"Because of the pronounced effect of interannual noise on decadal trends, a multi-model ensemble of anthropogenically-forced simulations displays many 10-year periods with little warming. A single decade of observational TLT data is therefore inadequate for identifying a slowly evolving anthropogenic warming signal. Our results show that temperature records of at least 17 years in length are required for identifying human effects on global-mean tropospheric temperature."
Now that another year has passed, we can include 2011 data in this analysis.
GISTEMP: Cool or Uncool?
Posted on 19 April 2012 by Kevin C
There are three main versions of the instrumental temperature record, HadCRUT3 from the UK meteorological office, GISTEMP from NASA, and the NCDC dataset from NOAA. Of the three, HadCRUT3 shows the least warming over the last 15 years, and GISTEMP shows the most. The difference is quite striking:
| Dataset | 1997-2012 trend |
|---|---|
| HadCRUT3v | 0.013 ±0.142 °C/decade |
| NCDC | 0.049 ±0.132 °C/decade |
| GISTEMP | 0.103 ±0.143 °C/decade |
Given the short-term cooling influences which have been operating over the last decade, the GISTEMP trend is much as expected. But the HadCRUT3 and NCDC trends are much lower.
In the previous article we examined the problem of sampling a stratified data set, and how this impacts the HadCRUT3 temperature record. We saw that the land temperature anomalies are both higher and have been increasing faster than ocean temperature anomalies. However land temperatures are under-represented in the HadCRUT3 data over the last decade, and the proportion of land temperatures has been declining. These effects both contribute to an increasing cool bias in the HadCRUT3 data.
Is there another source of bias which might explain the divergence of the three datasets? Studies from the ECMWF and GISS have indentified one such source in the HadCRUT3 data: Poor coverage at high latitudes. Can we find any evidence which might confirm this?
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