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Nuccitelli, D., Way, R., Painting, R., Church, J., & Cook, J. (2012). Comment on ocean heat content and Earth's radiation imbalance. II. Relation to climate shifts. Physics Letters A.
Cook, J., Nuccitelli, D., Green, S.A., Richardson, M., Winkler, B., Painting, R., Way, R., Jacobs, P., & Skuce, A. (2013). Quantifying the consensus on anthropogenic global warming in the scientific literature. Environmental Research Letters, 8(2), 024024+.
Nuccitelli, D. et al. (2014). Comment on "Cosmic-ray-driven reaction and greenhouse effect of halogenated molecules: Culprits for atmospheric ozone depletion and global climate change". International Journal of Modern Physics B.
Cook, J., Nuccitelli, D., Skuce, A., Way, R., Jacobs, P., Painting, R., Honeycutt, R., Green, S.A. (2014). Reply to Comment on ‘Quantifying the consensus on anthropogenic global warming in the scientific literature: a Reanalysis’. Energy Policy. DOI: 10.1016/j.enpol.2014.06.002
Nuccitelli, D. A., Abraham, J. P., Benestad, R. E., & Mandia, S. A. (2013). Comment on: Akasofu, S.-I. On the Present Halting of Global Warming. Climate 2013, 1, 4–11. Climate, 1(2), 76-83.
Abraham, J., Cook, J., Fasullo, J., Jacobs, P., Mandia, S., & Nuccitelli, D. (2014). Review of the consensus and asymmetric quality of research on human-induced climate change. Cosmopolis, 2014(1), 3-18.
Benestad, R. E., Hygen, H. O., Dorland, R. V., Cook, J., & Nuccitelli, D. (2013). Agnotology: learning from mistakes. Earth System Dynamics Discussions, 4(1), 451-505.
Nuccitelli, D., Richter, M. J., & McCall, B. J. (2005). A search for interstellar carbon-60. In IAU Symposium (Vol. 235, p. 236P).
Encrenaz, T., Bézard, B., Greathouse, T., Holmes, S., Richter, M., Nuccitelli, D., & Forget, F. et al. (2006, February). Ground-based high-resolution IR spectroscopy of Mars: H2O and H2O2 mapping, search for CH4, and determination of CO2 isotopic ratios. In Second Workshop on Mars Atmosphere Modelling and Observations, held February.
Recent blog posts
Posted on 8 February 2016 by dana1981 &
Congressman Lamar Smith (R-TX) has embarked upon a witch-hunt against climate scientists at NOAA, accusing them of conspiring to fudge global temperature data. However, a new study has found that the adjustments NOAA makes to the raw temperature data bring them closer to measurements from a reference network of pristinely-located temperature stations.
The adjustments are scientifically necessary
Before delving into the new study, it’s worthwhile to revisit the temperature adjustments that Lamar Smith disputes. Volunteers have been logging measurements from weather stations around the world for over 150 years, and climate scientists use that data to estimate the Earth’s average surface temperature. But over a 150-year period, things change, as the authors of this study explain.
To find out how much actual temperatures have changed, scientists have to filter out these changes in the way the measurements were taken. Those are the adjustments under attack from Lamar Smith. They’re important, scientifically justified, and documented in the peer-reviewed literature.
So what’s the controversy about?
Scientists make adjustments to account for changes in the way both land and ocean temperature measurements have been made over the past 150 years. The ocean adjustments make the biggest difference, and in fact they actually reduce the measured amount of global surface warming over the past century, as compared to the raw data. Thus you would think contrarians like Lamar Smith would appreciate these adjustments; however, over the past couple of decades, they act to very slightly increase the overall global surface warming trend.
Posted on 1 February 2016 by dana1981 &
In the 2016 Republican presidential candidate debates, climate change has rarely been discussed. In last Thursday’s debate, the last before tonight’s Iowa caucus votes, on Fox News of all networks, there was one brief climate question directed at Senator Marco Rubio (R-FL). Unfortunately it was framed as a ‘gotcha, flip-flop’ question, with Rubio asked about his apparent support 8 years ago for a carbon cap and trade system in Florida, versus his current opposition to the concept.Rubio responded:
In another debate 4 months ago on CNN, Rubio made similar comments, adding:
Fact checking Marco Rubio
Politifact ruled it “mostly true” that Rubio never supported cap and trade. However, the rest of his comments are mostly false.
Posted on 25 January 2016 by dana1981 &
2015 smashed the record for hottest year by about 0.14°C. To put that into perspective, the previous two hottest years (2014 and 2010) only broke the prior records by 0.002°C, according to Berkeley Earth data. The only time the temperature record was shattered by such a large margin was in the monster El Niño year of 1998.
While the current El Niño event is also becoming monstrously strong, it’s only now reaching its peak intensity, and there’s an approximately 4-month lag before changes in El Niño are reflected in global surface temperature changes. Thus, the El Niño of 1998 had a greater warming influence than its 2015 counterpart. 2015 was nevertheless more than 0.2°C hotter than 1998, due to human-caused global warming.
As the animated graphic below shows, there’s a consistent warming trend among El Niño years, La Niña years, and neutral years. Over the past 50 years, there’s a 0.16°C per decade trend among each category, and individual years fall close to those trend lines. That underlying human-caused global warming trend is what’s causing annual temperatures to so frequently break records, with 4 new record-hot years in the past decade.
Posted on 18 January 2016 by dana1981 &
Satellites don’t measure the Earth’s temperature. Senator Ted Cruz (R-TX) and his fellow climate contrarians love the satellite data, but as Carl Mears of the Remote Sensing Systems (RSS) satellite dataset and Ben Santer recently wrote,
Scientists process the raw microwave data, applying a model to make numerous adjustments in order to come up with a synthetic estimate of the atmospheric temperature. Climate scientists have identified many errors in the model, and so it’s undergone several major revisions. It’s a complicated process for many reasons discussed in greater detail in this new Skeptical Science myth rebuttal, and by Mears and Santer.
For example, satellites have a limited lifetime and are replaced (so far there have been 10 different satellites with MSUs); the MSU instruments change - they now use advanced MSUs (AMSUs); their orbits drift and decay due to friction; clouds get in the way; they have to isolate the data from the different layers of the atmosphere, etc.
In a recent Senate hearing, Ted Cruz and one of his witnesses, Judith Curry, claimed “the satellite data are the best data we have.” Most experts disagree.
Video by Peter Sinclair for Yale Climate Connections.
What makes “the best” the best?
At first blush the claim sounds plausible. After all, satellites are high tech! But how do we decide which data are “the best”? That’s a subjective question, but we can apply some objective criteria to answer it.
For example, as humans, we might consider the temperature where we live (at the Earth’s surface) the most important. Satellites estimate the temperature of the atmosphere, most of which is above us. In fact, as John Christy, who runs the University of Alabama at Huntsville (UAH) satellite dataset recently said,
Posted on 12 January 2016 by dana1981 &
Climate sensitivity – the amount of global surface warming we’ll see as a result of rising atmospheric carbon dioxide levels – has become contrarians’ favorite basis to argue against cutting carbon pollution. If the Earth’s climate is relatively insensitive to rising carbon levels, then it’s somewhat less urgent that we stop burning massive quantities of fossil fuels. However, a new NASA study indicates that’s not the case.
There are a few different ways that climate scientists estimate the Earth’s sensitivity to rising carbon. When they look at climate changes in the distant past (paleoclimate), and at simulations from complex climate models, they get about the same result: if the amount of carbon dioxide in the atmosphere doubles, temperatures will rise between 2°C and 4.5°C, most likely 3°C.
However, a few studies in recent years using a third method have yieldedsomewhat lower results. This method uses recent measurements of temperature and heat changes, combined with estimates of how “forcings” like the increased greenhouse effect have caused the Earth’s energy balance to change, all input into somewhat simpler climate models.
These results caused the latest IPCC report to drop its lower estimate of the likely climate sensitivity to double carbon dioxide from 2°C to 1.5°C. Climate scientists were faced with the question, why did this third approach (known as the “energy budget approach”) yield somewhat lower results than others, and which estimate is right?
A new study by Kate Marvel, Gavin Schmidt, Ron Miller, and Larissa Nazarenko at the NASA Goddard Institute for Space Studies appears to have found the answer. They drew upon previous research by Drew Shindell and Kummer & Dessler, who identified a flaw in studies taking the energy budget approach. Those studies had assumed that the Earth’s climate is equally sensitive to all forcings.
In reality, as world-renowned climate scientist James Hansen noted in a 1997 paper, some forcings are more efficient at causing the Earth’s surface temperature to change than others. Those in which the effects are focused in the northern hemisphere tend to be more efficient, for example. Andrew Dessler explains in the video below.
Posted on 4 January 2016 by dana1981 &
The Institute for Policy Integrity at the New York University (NYU) School of Law recently published a report summarizing a survey of economists with climate expertise. The report was a follow-up and expansion of a similar survey conducted in 2009 by the same institute. The key finding: there’s a strong consensus among climate economics experts that we should put a price on carbon pollution to curb the expensive costs of climate change.
The survey participants included economists who have published papers related to climate change “in a highly ranked, peer-reviewed economics or environmental economics journal since 1994.” Overall, 365 participants completed the survey, which established the consensus of expert climate economists on a number of important questions.
Carbon pollution cuts are needed regardless of what other countries do
In the 2009 version of the survey, the respondents were asked under what conditions the United States should commit to reducing greenhouse gas emissions. 57% answered that the US should cut its emissions no matter what actions other countries take, while another 38% said that American emissions cuts would be warranted if many or all other countries commit to reducing theirs (as just happened in the Paris international negotiations).
In the 2015 survey, the number of expert economists saying that the US should cut its emissions no matter what rose to 77%. A further 18% said that if other countries agree to cut their emissions, the US should follow suit. In other words, there is a 95% consensus among expert climate economists that the US should follow through with its pledges to cut carbon pollution in the wake of the Paris international climate negotiations, and more than three out of four agreed that the US should take action to curb global warming no matter what.
This expert consensus is in stark contrast to conservative political opposition to the Paris accord. For example, Republican presidential candidate Marco Rubio said of the agreement,
Posted on 21 December 2015 by dana1981 &
Every year, the world’s Earth and space scientists converge on San Francisco forthe fall American Geophysical Union (AGU) meeting. Around 25,000 scientists attended this year, most of whom do research relevant to climate change. I’ve just returned from the conference, at which I was struck by the quality and quantity of fascinating research and people.
Great humans, under attack
I had the pleasure of meeting with dozens of climate scientists, and they were without exception kind, brilliant, fascinating people with a passion for learning how the Earth’s climate functions and how humans are changing it. It was a stark contrast from the way the climate science community is often portrayed – as frauds, conspiring to falsify data as part of the greatest hoax ever perpetrated.
These claims have been made by several American political representatives, including Senator James Inhofe, Congressman Lamar Smith, and Senator (and leading Republican presidential candidate) Ted Cruz. Recent comments made by Smith and Cruz attacking climate scientists and misrepresenting their data were referenced in at least three talks at the conference.
Climate scientists are understandably unhappy with the way their and their data and research are being misrepresented by these politicians. These types of distortions have led to countless personal attacks on climate scientists. I spent time with Michael Mann, Raymond Bradley, and Malcolm Hughes, who were attacked because they published groundbreaking research reconstructing past temperatures that resulted in the ‘hockey stick’ that certain parties found politically inconvenient. Mann and Bradley have written books documenting their journeys in navigating these attacks.
Posted on 14 December 2015 by dana1981 &
In stark contrast to the shortcomings of previous international climate negotiations, the Paris COP21 talks have ended with an agreement stronger than most expected. Graham Readfearn summarized the agreement for The Guardian.
In short, leaders from around the world have agreed that we must do everything we can to slow global warming as much as we can, submitted pledges to begin the process of cutting carbon pollution, and created a framework by which those pledged cuts can be expanded and strengthened to achieve the goal of limiting the damages of human-caused climate change. There was unanimous agreement about this including from Saudi Arabia, China, India, and the USA. President Obama hailed the agreement at the White House.
Posted on 8 December 2015 by dana1981 &
In 2008, a paper was published in the journal Nature predicting that global surface temperatures would cool slightly in the years 2005–2015 as compared to 1994–2004. The authors of that paper thought that during that time, the cool phase of natural ocean cycles would be enough to more than offset warming from the increased greenhouse effect, before human-caused global warming caught up again thereafter. At the time, the paper and its cooling prediction received a tremendous amount of media attention.
There was some truth to the prediction. From about 1999 to 2012, there weremore La Niña than El Niño events, with the former having a short-term cooling influence on global surface temperatures, and the latter having a short-term warming effect. So, it’s true that natural ocean cycles had a temporary cooling effect during that time period.
But, the authors of the paper predicted that global surface temperatures would fall. The climate scientists who blog at RealClimate were so confident that temperatures would continue to rise that they offered the authors a bet.
The authors of the paper declined to accept the bet, which was a good decision, because it turns out they would have lost. Despite the temporary cooling influence of natural ocean cycles and low solar activity since 1999, temperatures have continued to rise due to the strength of the increased greenhouse effect. They have risen more slowly than they would have otherwise, but temperatures have continued to rise nevertheless. As the climate scientists at RealClimatewrote,
Posted on 30 November 2015 by dana1981 &
The burning of fossil fuels for energy and animal agriculture are two of the biggest contributors to global warming, along with deforestation. Globally, fossil fuel-based energy is responsible for about 60% of human greenhouse gas emissions, with deforestation at about 18%, and animal agriculture between 14% and 18% (estimates from the World Resources Institute, UN Food and Agriculture Organization, and Pitesky et al. 2009).
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