MOSCB Workshop at MONRC
by Alan Journet, MOSCB President
Part One
During the annual Missouri Natural Resources Conference held January 30 – Feb 1 2008, The Missouri Chapter of the Society for Conservation Biology (MOSCB) organized a workshop entitled “The Potential Impact of Climate Change on Missouri Biodiversity” featuring a series of presentation and an open forum question/ answer session. The following summary was written for ‘The Glade’, the newsletter of MOSCB and is reprinted here by permission of the Executive Board.
The Intergovernmental Panel on Climate Change (IPCC) started releasing its Fourth Assessment Report (AR-4) in February 2007 with the Summary for Policymakers. Three statements contained in the report are of relevance to this workshop: “Warming of the climate system is unequivocal.” “Most of the observed increase in globally averaged temperatures since the mid 20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.” Very likely is defined as > 90%. “The understanding of anthropogenic warming and cooling influences on climate has improved since the Third Assessment Report [TAR 2001] leading to very high confidence that the globally averaged net effect of human activities since 1750 has been one of warming, with a radiative forcing of + 1.6 (range 0.6 – 2.4).” Again very high confidence is defined as > 90%. Considering that this report was subject to the review and modification of politicians – who tend to minimize the risks, the likelihood is that these levels of probability represent underestimates of the confidence of the climate and atmospheric science community concerning these conclusions.
With the 2006 release of Al Gore’s award winning movie ‘An Inconvenient Truth’ and his gaining a Nobel Prize for the effort, the fourth Assessment Report of the IPCC could not have been released at a more timely moment. As a result, the chapter decided at its 2007 Annual Meeting to organize a workshop at the 2008 Missouri Natural Resources Conference entitled “The Potential Impact of Climate Change on Missouri Biodiversity.” The session, featuring an introduction on Missouri climate history and predictions featured state climatologist Pat Guinan of the Univeristy of Missouri-Columbia, was followed by Bill Eddleman from Southeast Missouri State University discussing the possible consequences for birds, John Landosky from the University of Missouri- St Louis discussing insect responses, Bethany Williams of the University of Missouri-Columbia discussing herp responses and Nadia Navarrete- Tndall exploring the same for plants. Tim Nigh of Missouri’s Conservation Department then discussed the consequences for Missouri’s ecological land types, and Dennis Figg (for whom Rick Thom was pinch-hitter since Dennis was unfortunately sick), also of MDC, discussed the Missouri Comprehensive Wildlife Strategy in relation to climate change consequences. These presentations were followed by a lively question-and answer panel discussion with audience members offering their thoughts and questions regarding the issue.
Pat Guinan started the workshop by pointing out that Missouri’s long term temperature history indicated a slight warming over the last decade compared to the long term (100 year app.) average. However, he noted that the current warming is no greater to date than has been experienced in the past. Indeed, he pointed out that periods in the 1930s and 1950s were actually warmer than recent overall temperatures. However, in breaking the pattern down into climatic seasons, Guinan pointed out the warming we are currently experiencing is largely a consequence of our enjoying warmer winters (Dec – Feb) and springs (Mar – May), with no detectable warming occurring during summers (Jun – Aug) and only slight warming during falls (Sep – Nov). Guinan concluded his historical temperature account by noting that Missouri’s warming trend began only as recently as 1998 compared to the global trend – which began in 1977. He noted that four of the five warmest Missouri winters on record have occurred since 1991. Not surprisingly, winter snowfall has thus declined. Meanwhile, in terms of precipitation, Guinan indicated that from the early1980s to three years ago, Missouri enjoyed an unprecedented wet period with 17 of the 24 years experiencing above normal precipitation. He closed with the cautionary warning that maybe a redressing drought period is on the near horizon.
In addressing the future, Guinan noted that Missouri has no independent predictive data, but that he based his estimate on data computed by the Illinois State Water Survey using IPCC data, suggesting that Missouri will probably be equivalent. These models suggest that Missouri will experience over the next 100 years a temperature increase of 30F – 70F but no clear trend in precipitation – suggesting it may not change from current patterns.
In terms of the widely accepted dominant driving force of climate change, carbon dioxide concentration, Guinan offered three models that vary in accordance with the assumed extent to which humanity responds to the problem. These estimates range from just under 550 ppm to 850 ppm by the end of the century. It is worth comparing this to the current value of just over 380 ppm and the pre-industrial revolution value of about 270 ppm. (e.g. Wigley 1983). The one hundred year prediction, therefore, is between 2 and over 3 times the eighteenth century concentration.
In summary, by 2050, the climate of southeast Missouri may well emulate that currently evident in Central Arkansas, while by 2100 the southern tier of Missouri counties may be experiencing the current climate of Northern or Central Louisiana.
Bill Eddleman introduced the topic of possible bird consequences by reporting an American Bird Conservancy prediction that the range of the American Goldfinch may be, under the climate induced by a doubling of carbon dioxide, such that Missouri is no longer included – the range having shifted north – except for a refuge in the Rocky Mountains. Eddleman then suggested that the mechanism impacting birds could be: range shifts, productivity changes (with greater, equal, or lower productivity having been suggested as consequences), habitat loss or alteration, shift in migration timing. Of 96 migrant species in Manitoba, he reported, fully 27 arrive significantly earlier, while only 2 arrive later. Meanwhile, of 13 North American species studies, 6 depart later; some species are even foregoing migration altogether at higher rates than previously. An additional mechanism involves a change in clutch initiation; among a multiplicity of examples, Eddleman selected the tree swallow which has advanced clutch initiation 9 days during the last 30 years. This led to a discussion of the problem that climate change is inducing asynchronicity between the migratory behavior – particularly arrival and clutch initiation of birds – and the availability of food. Thus long distance migrants (the behavior of which is probably induced by photoperiod – an environmental cue unaffected by climate change) seems less likely to adjust their patterns, while food availability (in many cases such as insects – is dependent on day-degrees and thus temperature for its development) shifts earlier in the season. Thus migrants may miss the peak food availability upon which successful nesting depends. In addition to average temperatures impacting birds, Eddleman noted that increases in the frequency of climatic extremes (such as drought) may well tip the scale against some species. In the category of synergistic effects – where climate change consequences combine to generate unfavorable conditions, Eddleman pointed out that some species already in decline may well be ‘pushed over the edge.’ In reviewing the possible consequences for Missouri’s birds, Eddleman suggested responses will likely comprise: little change in breeding range, contraction of the breeding range possibly to the point of exclusion, and of course, expansion of breeding range, with the addition of species to the state. Eddleman then reported on what the evidence, from such assessments as the Breeding Bird Survey, indicates has already occurred. He identified species according to the likelihood that their future range will be little influenced, may contract or result in their exclusion from the state, or may expand and result in their appearance in Missouri.
In closing, Eddleman suggested that the evidence on patterns to date indicates minimal impact, but that it would be difficult to separate effects of climate change (whether direct or indirect) from impacts of factors other than climate change that may be independently decreasing habitat.
See part two in next issue of the MO Sierran for continuing information on how climate change may impact Missouri’s insects, amphibians, reptiles, forests and a consideration of shifting ecoregions.