Region: NATIONAL U.S. average temperatures in the urbanisation-adjusted Historical Climate Network of Karl at ala. UL: Daily Maxima: LL: Daily Minima; UR: Daily Average: LR: Daily Range (Difference between high and low). The decline in daily range occurs because of a relative rise in nighttime temperatures, indicating that the possible greenhouse compensation is taking place primarily at night, while daytime temperatures have actually declined. it Analyses through 1987 show that this trend has continued. This could be cause either by increased cloudiness, which has been noted in four reports in the refereed scientific literature, or by the infrared absorbing effects of anthrpogenerated trace gases. It is more likely that the reduction in daily range results from a combination of the two. The pecularity is that if such a trend continued, greenhouse world could be one where growing seasons were longer (because nighttime temperatures increased), there was more precipitation and less skin cancer (because of increased cloudiness) and plants grew better (because of the well known effect of carbon dioxide fertilization). The "positive" vision of future climate was recently presented by Soviet Academician Mikhail Budyko, in a paper first read at a NOAA sponored meeting of the Climate Trends Panel last September. Budyko's position in the Soviet science establishment is roughly analogous to being in the highest echelons of our National Center for Atmospheric Researach. I only bring it up to underscore the broad range of expert opinion that exists on this subject. With regard to observed temperature changes, the:current draft of the Climate Trends Panel meeting proceedings states that "the overall magnitude of the surface warning since the latter 19th century...is about half of that expected by most GCM simulations given the best estimate of changes-in greenhouse gases over period." 4. The Urbanization Problem. this It is well known that long term climate records sometimes warm because their surroundings become more urbanized, and while much has been written on this problem, it remains elusive. In the March, 1989, issue of the Bulletin of the American Meteorological Society, NOAA scientist Tom Karl will publish a paper that compares NASA climate recorda over the U.S. to the urbanizationadjusted Historical Climate Network. The paper will show that the published NASA record warms up 0.4 in the twentieth century compared to the unurbanized record. It is important to note that there is no a priori reason to suspect that the urban bias is appreciably different in other portions of the industrialized world. A simple extension to the globe--which is not possible to rigorously defend at this time because the exhaustive research has not been performed--would yield a residual warming of 0.20.3, an amount which is three times less than that predicted by the average of our sophisticated climate models. The other popularly cited climate record, of the East Anglia research group, leaves essentially the same residual in an analogous comparison. A slightly different analysis finds virtually no change in conterminous U.S. temperatures over the last century, which is size of the U.S. can continue to be cooler than the rest of the world for periods of decades. However, analogous studies of Canadian data and my mean layer temperature calculations for Alaska show that indeed the area of no significant temperature change over the last 50 years is virtually all of North America. It is doubtful that this can be accomodated by a transient climate model with a realistic change in trace gas concentrations over that period. It would be important to extend these types of analyses to other regions with analogous urban/rural climate networks, such as the Soviet Union. I urge that you give what would have to be a joint effort your highest priority. In addition, I urge the support of other important investigations that will help us determine earth's true temperature history and to find in fact how the change in trace gases will eventually be expressed. the These observations are not intended to minimize the importance of the climate change problem, but rather to emphasize its complexity. I enact find it extremely risky to sweeping environmental policy based upon visions that are at best clouded, and at worst already failing. Further, if models that eventually fail are used as the lynchpin for an otherwise rational energy policy, that policy could eventually suffer a serious loss in credibility which would set back progress on these important issues for decades. KASA's record over the coterminous U.S. warms approximately 0.4° C compared to the urbanisation-adjusted historical climate network. If such a trend occurred throughout the rest of the world,,net global warming for the 20th century would be 0.2-0.3°C, which is virtually indistinguishable WORLD. Volume 1 No. 4 Report Climate A BI-WEEKLY REPORT ON GLOBAL CLIMATE CHANGE "TORRENTIAL" RAINS INCREASE! See Back Side one more day every two years in which rainfall exceeds two inches. Apparently. as reported in our last issue ("Karl Finds "No Smoking Gun, Vol. 1, No. 3), this is definitive proof that global warming is here. Why does a little extra rain in the central United States demonstrate global warming? Don't look for answers here-we have no idea. But since this study has garnered so much media attention, let's look at it a little more closely. In a paper that appeared in the British journal Nature in September, Tom Karl, Richard Knight, and Neil Plummer examined trends in global land-based temperature and precipitation. Since similar temperature analyses have appeared elsewhere, the precipitation results gamered the most attention. Using the Historical Climate Network (the best data set for analysis of long-term trends since it is largely rural and has been subjected to significant quality control), based on aggregated daily records from more than 180 stations in the United States, Karl found significant trends in the yearly frequency of annual precipitation accounted for by "extreme" precipitation events (greater than two inches per day) Most of these heavy rains fall during summer. However, there is no overall precipitation trend because of decreases in several lighter precipitation categories. Vice-President Gore referred to these as increases in torrential rains." But we ask the following questions: 1) How "significant" are these trends? 2) Are they worth worrying about? 3) Are they indicative of global warming? 4) Are these rains really torrential? We examined a large subset of the same data set used for summers (June through August) from 1910 to 1987; but, rather than averaging the data, we looked at the trends for individual stations. For each station, we computed the percentage of summer rainfall of more than two inches per day. A glance at the map shows most of the trends in the United States are indeed positive. But only four out of the 120 stations have statistically significant trends. This is fewer than would be expected by random chance. Is the definitive proof of global warming really a few more days of summer rain in Highmore, South Dakota, and Gothenburg. Nebraska (or the other two stations with significant trends)? Karl et al. state that there are few positive trends in the other countries they examined. Hmmm... Let's suspend disbelief for a moment and assume that these trends are meaningful. Is this really a problem? Most agricultural regions in the United States benefit from summer rain since this is the time of year when evaporation is highest and a plant's need for water the greatest. Ask any com grower if he would prefer an extra two-inch rainfall in midsummer. Assuming the Government's not paying him to lose money that year, his answer will be "#$%@, yes!” Are more heavy summer rains in the United States a global warming indicator? In the United States, daytime temperatures (which provide the fuel for thunderstorms) have actually declined over the last seven decades. To make conditions more unstable (conducive to thunderstorm formation). we have to cool the atmosphere from 20,000 to 50,000 feet; but all computer climate models predict warming in this layer. So, does this alleged global warming indicator invalidate these models? Further, how torrential" are these rains? How accurate is the image of fields of com being washed away by these cloudbursts? We mapped the percentage of heavy rainfall (greater than two inches per day) accounted for by three-inch-per-day or greater rain events. Except for the Gulf Coast region, few instances of more than three inches of ast issue of this Report caused quite a stir when we alleged that all was not proper in the review process for the United Nations Intergovernmental Panel on Climate Change (IPCC). Specifically, we mentioned unfindable references and denial of specific data critical to a proper independent evaluation. This finding comes at a critical juncture in the climate change issue. The Clinton Administration has just announced that its Climate Change Action Plan- the "voluntary program to reduce carbon dioxide emissions to 1990 levels by the year 2000-has failed. Not coincidentally, global warming rhetoric is at high crescendo. Something's about to give, and we would not be surprised if the Administration soon proposes tradeable emission permits for greenhouse gases. They'll correctly predict that Congress will have no part of it, and forge a big issue for the 1996 election. All of this, of course, depends largely upon the reliability of global warming science, and it is the IPCC that claims to be the colossus of credibility. If their review process is tainted, so is their science. In the course of reviewing their new report, this editor noticed that the climate model that IPCC said best tracked the past climate (and therefore is most reliable in the future) only reduced its warming forecast for the high latitudes of the Northern Hemisphere for 2040 by 1°C to 2°C, and forecast a rise of 4°C to 6°C. This was of some concern, because older models, which are now acknowledged as inaccurate, predict that those latitudes should have warmed some 2oC since 1950. The actual warming is zero. This would seem to mean that even the more "reliable" model is still making a large polar error and is too warm in the future. (Report Vol. 1, No. 2, tells how much the model's forecast warming has been reduced.) But that hypothesis could only be checked for truth if one compared the patterns of model behavior over the high Arctic with the patterns of reality as the greenhouse effect has changed. Electronic Mail to U.K. Meteorological In writing my review of the "In view of the interests of my collaborators who have invested a lot of effort in producing these results. I feel it inappropriate to send you gridpoint data at present." Electronic Mail to UKMO, May 11, 1995: I do not understand your statement....Science is a cooperative effort in which information should be freely shared....While I understand your feelings about the proprietary nature of results that are not yet published, your Nature paper will clearly be published long before reviews of IPCC are integrated. It 15. in my mind, not proper to withhold scientific information to a colleague who has been asked by the IPCC itself to review its own work....I therefore ask you to reconsider your decision not to send me the gridded output from the models." UKMO then sent two papers that were in review. One has been published in Nature, as the e-mail mentions. Electronic Mail to UKMO, May 12, 1995: Thank you for sending the paper.... It is apparent that you are not sending me the time series of the gridded latitudelongitude output from the models. I respect your decision. although I do not agree with it". Reply from UKMO, May 12, 1995: The data will be made available (within reason) at a later date." Electronic Mail to UKMO, May 16, 1995: The reason I am so interested in the gridded data stems from [UKMO goes on to refer to an unpublished manuscript on which we have agreed to make no public comment-Ed.)....conse. quently, it would be my working hypothesis that even a sulfate modified GCM (the type that best tracks past climate) would still be producing a large (and erroneous! arctic winter warming.... Perhaps now you see why I am so interested in the gridded timeseries. Maybe you'll reconsider? I am sorry to trouble you but I hope you agree that the credibility of the Atmospheric Sciences-everything we have worked for-lies in the global warming issue." World Climate Report is a research review edited by Patrick J. Michaels Funding for this publication is provided by |