- Global climate is changing, and this is apparent across the U.S. in a wide range of observations. The climate change of the past 50 years is due primarily to human activities, predominantly the burning of fossil fuels.
- Some extreme weather and climate events have increased in recent decades, and there is new and stronger evidence that many of these increases are related to human activities.
- Human-induced climate change is projected to continue and accelerate significantly if emissions of heat-trapping gases continue to increase.
- Impacts related to climate change are already evident in many sectors and are expected to become increasingly challenging across the nation throughout this century and beyond.
- Climate change threatens human health and well-being in many ways, including impacts from increased extreme weather events, wildfire, decreased air quality, diseases transmitted by insects, food, and water, and threats to mental health.
- Infrastructure across the U.S. is being adversely affected by phenomena associated with climate change, including sea level rise, storm surge, heavy downpours, and extreme heat.
- Reliability of water supplies is being reduced by climate change in a variety of ways that affect ecosystems and livelihoods in many regions, particularly the Southwest, the Great Plains, the Southeast, and the islands of the Caribbean and the Pacific, including the state of Hawai`i.
- Adverse impacts to crops and livestock over the next 100 years are expected. Over the next 25 years or so, the agriculture sector is projected to be relatively resilient, even though there will be increasing disruptions from extreme heat, drought, and heavy downpours. U.S. food security and farm incomes will also depend on how agricultural systems adapt to climate changes in other regions of the world.
- Natural ecosystems are being directly affected by climate change, including changes in biodiversity and location of species. As a result, the capacity of ecosystems to moderate the consequences of disturbances such as droughts, floods, and severe storms is being diminished.
- Life in the oceans is changing as ocean waters become warmer and more acidic.
- Planning for adaptation (to address and prepare for impacts) and mitigation (to reduce emissions) is increasing, but progress with implementation is limited.
Sunday, January 13, 2013
The Third National Climate Assessment (NCA) Report has just been released for public review. I will not comment on the content of that report here. That will come later. This week I simply ask who it is that produced this report and can they be trusted?
In 1989 President Bush established the U.S. Global Change Research Program (USGCRP), which was authorized by Congress in 1990. This program has coordinated the efforts of 13 federal departments and agencies (see graphic) for over two decades.
In December 2010, the National Climate Assessment and Development Advisory Committee (NCADAC) was established under the Department of Commerce and supported through the National Oceanic and Atmospheric Administration (NOAA). It is a federal advisory committee (Federal Advisory Committee Act of 1972) under the auspices of the USGCRP. It continues the work of previous such committees.
The mission of the NCADAC is to "synthesize and summarize the science and information pertaining to current and future impacts of climate change upon the United States; and to provide advice and recommendations toward the development of an ongoing, sustainable national assessment of global change impacts and adaptation and mitigation strategies for the Nation" (Aug 2011). Their first task is to "integrate, evaluate, and interpret the findings of the USGCRP and discuss the scientific uncertainties with such findings". This committee reports to the USGCRP through the Undersecretary of Commerce for Oceans and Atmosphere.
Previous National Climate Assessment (NCA) reports from the USGRCP were made in 2000 and 2009. According to the National Research Council, these demonstrated that "An assessment can establish the importance of an issue, provide an authoritative resolution of policy-relevant scientific questions, demonstrate the benefits of policy options, identify new research directions, and provide technical solutions".
What about this report?
(1) This assessment report is the outcome of a process that is both scientific and political. The political aspects, however, are assuaged by the fact that the process has occurred over more than two decades under four different administrations from both major parties.
(2) The process has been overseen by thirteen agencies and departments. While it is true we don't know how closely each of these federal entities have followed the developments, all of them bear responsibility and some of them (NOAA for example) are intimately involved.
(3) This specific committee has deliberately sought to engage a broad spectrum of stakeholders, and the committee set up a number of ways for this to occur.
(4) The report is authored by over 240 individuals. I don't know them personally, but the diversity of the group is impressive and their credentials impeccable. The transparency of the entire process is reassuring.
(5) The report is now open to public comment. If you take issue with any conclusion, statement, word, or punctuation mark, you may go to the Review and Comment System and provide your input. Furthermore, the National Academy of Sciences is specifically enjoined to participate in this review.
What is my opinion?
I am inclined to take this report seriously.
Tuesday, January 8, 2013
In the conversation yesterday, we came across the following statement by climatologist Dr. John Christy: "I've often stated that climate science is a 'murky science'. We do not have laboratory methods of testing our hypotheses as many other sciences do."
My first response was "yes he is right." I am no climatologist, but I have tried to read enough of its foundational literature to understand that climate science is complicated. No, it is extremely complicated. It is often based on enormous data sets, complex statistical analysis, and tedious attention to detail. It is also based upon weaving together the principles of physics and thermodynamics, chemistry, biology, geology, and other disciplines. Weather is the state of the atmosphere for a given location at any given time; climate is the weather of a wider region over a longer period of time. Both are extremely complicated; I admit this.
Have I mentioned that climate science is complicated?
On further reflection, however, climate science is not a 'murky science' simply because it is complicated, nor because it does not have laboratory methods for testing its hypotheses. There are many such sciences. They are called observational, descriptive, or historical. Examples include astronomy, geology, paleontology, epidemiology, and many of the social sciences. The job isn't particularly easy, but scientists engage in this type of investigation all the time. How do they do it?
There are two main techniques in observational science: (1) multivariate statistical techniques, and (2) making predictions of previously unobserved phenomenon based on current knowledge as hypotheses for further testing. Both of these methods are used to good effect in climate science, but both have potential pit falls. In the case of statistical analysis, the proper sequence is far from intuitive. Whether one subtracts before averaging or averages before subtracting can make significant difference in one's viewpoint. The same goes for computing variability before or after averaging. In the case of making predictions, one runs the risk of setting up non-falsifiable hypotheses.
There are many similarities between this situation and the study of cancer, heart disease, and stroke. The causes of these diseases are multi-factorial, meaning that they are complicated. Furthermore, biomedical scientists can't very well do randomized controlled experiments on people and their life-styles. But through sophisticated statistical techniques, epidemiologists have been able to sort out the many variables to show that cigarette smoking is a significant causal factor in all three. Because of the statistical nature of the investigations, however, the results were questioned long after they were conclusive.
I have not always had strong opinions about the topic of climate change. I've not even been a very good advocate for the environment despite my concern for it. By the time I started paying attention to "global warming" a few years ago, it had become so controversial I was not sure what to think. I was sympathetic but also confused. For the past two years, however, I have put significant time and effort into increasing my knowledge and understanding. I am no climatologist and never will be, but where I am today is that the evidence I have seen so far has convinced me that anthropogenic global warming is real and that it will become a crisis for our planet if no changes are made.
Since I did not start out with this belief, I do not consider this a "bias". Nevertheless, because that is my position now, as I proceed to take an even closer look at climate science over the coming months, I will make a concerted effort to sort out non-falsifiable hypotheses and try to avoid unwarranted oversimplifications.
Climate science is complicated (perhaps even more complicated than rocket science), but that doesn't mean we shouldn't try to understand it, and maybe it isn't quite as 'murky' as we are told.
Sunday, January 6, 2013
Recently I've had the pleasure of engaging in an online conversation about climate change in which one of the participants agrees that the Earth is possibly warming but disagrees that human activity is the cause.
"Any climatologist who tries to say they know [that global warming is cause by humans] would be lying. We have only been measuring temperature accurately since the 19th century, and there is no way one could tell the difference between human cause or natural cycle with such a short data set."This comment deserves a response, which I will get to shortly, but first I must summarize the other objections posted.
- A link was posted to the HadCRUT dataset along with a note critical of one of the methods explanations, the implication being, I suppose, that the entire data set might be invalid.
- A link was posted to a news article about the Earth's' magnetic field fading, with a note that the following is all I need to read: "Today it is about 10 percent weaker than it was when German mathematician Carl Friedrich Gauss started keeping tabs on it in 1845, scientists say."
- A link was posted to Is the earth spinning slower? with the corollary that the moon is moving away from the earth by 3.8 cm/yr.
- A link was posted to a copy of an article DMI polar data shows cooler Arctic temperature since 1958.
Now the first thing to say is that these objections cannot, or at least should not, be dismissed with a mere wave of the hand. Not only were they offered in complete sincerity, which I appreciate, but most of them carry some weight with at least a certain segment of the population and most of them also carry a grain of truth that could be important. The next thing for me to say is that I didn't (and don't) find any of them persuasive, although I did take them seriously enough to research and write this post.
Objections (3) and (4) were offered together, the hypothesis being: (a) The moon effects oceans tides; (b) The tides influence ocean currents; (c) If there is less pull (and less angular momentum) due to the greater distance, then the currents that carry the heat away from the equator to the cooler regions will be diminished; (d) This means that more heat stays in the atmosphere instead of being sinked (sic) away to cooler waters in the ocean; (e) Thus we should see a cooling trend in the arctic, as demonstrated in the DMI data as interpreted by Lansner.
Objection (3). The distance of the moon from the earth varies over the course of its orbit from 356,700 km at perigee and 406,300 km at apogee. This is a difference of more than 12% each month (29.5 days). The grain of truth here is that when the moon is at apogee it does have less gravitational pull, which can contribute to lower variation in the high/low tide level. When the moon is at perigee there is more gravitational pull, which contributes to greater variation in the high and low tide. The problem with my interlocutor's argument is that 3.8 cm/yr over the course of even 150 years (let alone 30) is less than 0.03%. Even if we agree that averages are more important than ranges, a change in distance of << 0.1% over more than a century does not account for much. Incidentally, there are factors other than the moon's distance which affect the tides, most of which tend to dampen the moon's affect.
Objection (4). Without (3) there would be little or no explanation for (4) were it to be valid, but it needs to be considered on its own merits. So what are we to make of the fact that DMI reported an apparently cooler Arctic temperature from 1958 to present? First it should be noted that DMI itself never interprets its own data in the way that (4) does. In fact, DMI is concerned that not enough attention is being paid to the dire consequences of permafrost melting in the Arctic, but that is another matter.
What Lansner did in (4) was to take the thawing season out of context. Let me make this a simple as I can. In the winter the average temperature gets very low in the arctic (<-10 F, <-25 C) and there is much variability. In the thawing season, it never gets much above freezing (32 F, 0 C) because if it does, the ice melts cooling the air above it. In fact, let me just speculate. What if the "cooling" trend observed by the DMI is due to higher ocean temperatures or in any case a higher rate of ice melting? Pure speculation on my part, but my argument does not depend on it. The important SCIENCE is that annual average Arctic air temperatures have increased over the past few decades at a rate around twice the global average, and this is well documented. That is the crux in a nutshell, and anyone interested in the details can find them at Skeptical Science.
In a follow-up comment my interlocutor dismissed the Skeptical Science article by misinterpreting the explanations of the different datasets as a criticism of the DMI methods. True, the article discusses at length the strengths and weakness of several different methodologies, but the point was not to say that one is more valid than another. The Skeptical Science criticism of (4) is not that the DMI data should be considered invalid, but that DMI, GISS, and others all point in the same direction. The annual average Arctic temperature has risen sharply in recent decades. They all agree on this trend. Lansner (4) disagrees because he looks at only two months out of the year.
(I mean no disrespect, but can anyone tell me who Frank Lansner and Nicolai Skjoldby are, or their credentials? Apparently the latter has an M.S. in Forestry from the Royal Danish University of Agriculture, but other than that I can find nothing online about either one.)
Objection (2). The article per se is not about climate change. My interlocutor has used it, however, to offer the hypothesis that "a 10% reduction in the earths magnetosphere means a 10% increase in solar radiation to the earths surface." Uh, no. Not true. A magnetic field has no effect whatsoever on electromagnetic radiation in any part of the spectrum. What the magnetic field does, however, is protect the Earth from the solar wind (charged particles). This is important, of course, but it is unrelated to the amount of radiant energy received from the sun. — Entirely unrelated, it was suggested that somehow the fact that we only have temperature measurements back 150 years and that we have only been measuring the Earth's magnetic field for 150 years is somehow significant. First, that coincidence is not significant. Second, in both cases (temperature and magnetic fields) we have proxy measurements going back much further. The further back, of course, the less precise or reliable, but the information is still useful.
Objection (1). I am not sure (1) was actually offered as an objection, but this reminds me to begin working on a discussion of surface air temperature measurements.
Going back to the original comment, there are two aspects that each deserve a much more thorough response than I can provide this morning. The first is about the nature of science in general and climate science in particular. Scientists do not "try to say they know" anything with certainty. What they do is present the evidence and their interpretation of that evidence. The evidence is for anthropogenic global warming is strong, and most climate scientists interpret it that way. The second is that my interlocutor states emphatically that the temperature measurement record is too short to allow any climate scientist to come to a valid conclusion about the source of global warming. My only response at the moment is that (a) even 150 years of temperature data provide powerful evidence, and (b) there are many other kinds of evidence that corroborate that conclusion. (Sigh, never enough time.)
Thursday, January 3, 2013
For the past 72 weeks I have made a donation to a worthy cause in the name of each Facebook friend having a birthday that week. My goals have been: (1) to honor each friend on his or her birthday, (2) to raise awareness of needs around the world, (3) and to financially support causes that help meet these needs. In doing this I have made a concerted effort to steer clear of issues or organizations that might be considered controversial.
This coming year (2013), I want to continue the practice of recognizing my friends' birthdays, but I feel called to focus on the issue of Global Warming and Climate Change. For some this may be controversial, and I don't particularly wish to stir up trouble, but this is a matter that is too crucial to shy away from. For those who may be uncomfortable having a gift made in your name to an organization active in the politics of climate change (such as 350.org), you may choose one of the other two (Oxfam America and Touch the Jungle).
The first provides direct action against climate change, the second helps mitigate some of the devastation caused by global warming, and the third helps on a local level in Ecuador. Something for everyone. :-) After I came up with this idea, it occurred to me that I will look forward to hearing where each of you prefers your gift to go.