Tuesday, September 9, 2014

Climate Change Conservation News



News related to the accelerating global warming crisis has captured the headlines this week. Today the World Meteorological Organization (WMO) released its annual Greenhouse Gas Bulletin, announcing that “The amount of greenhouse gases in the atmosphere reached a new record high in 2013, propelled by a surge in levels of carbon dioxide.” The WMO reports: “The observations from WMO’s Global Atmosphere Watch (GAW) network showed that CO2 levels increased more between 2012 and 2013 than during any other year since 1984. Preliminary data indicated that this was possibly related to reduced CO2 uptake by the earth’s biosphere in addition to the steadily increasing CO2 emissions.” It is not surprising then that 2013 tied with 2003 as the fourth warmest year on record, and May of this year was the warmest ever recorded. Today’s announcement from WMO has “injected even greater urgency into the need for concerted international action against accelerating and potentially devastating climate change.”  

Our rapidly changing climate is already having serious consequences for human and wildlife communities alike. From unprecedented ocean acidification that is killing off vast expanses of coral reefs, to megadroughts that threaten to further exacerbate major water shortages in major cities and drought-driven high raptor nest failure rates in southern California, no place on Earth is immune to the reach and consequences of global warming.

Birds are an important barometer for predicting and measuring the impacts of climate change. The Climate Report, released today by the National Audubon Society, predicts many potentially dramatic changes and challenges our birds will face under various climate change scenarios. The new report “is a comprehensive, first-of-its kind study that predicts how climate change could affect the ranges of 588 North American birds. Audubon scientists used three decades of citizen-scientist observations from the Audubon Christmas Bird Count and the North American Breeding Bird Survey to define the “climatic suitability” for each bird species—the range of temperatures, precipitation, and seasonal changes each species needs to survive. Then, using internationally recognized greenhouse gas emissions scenarios, they mapped where each bird’s ideal climatic range may be found in the future as the climate changes. These maps serve as a guide to how each bird’s current range could expand, contract, or shift across three future time periods (2020, 2050, and 2080). Of the 588 North American bird species Audubon studied, more than half are likely to be in trouble. Our models indicate that 314 species will lose more than 50 percent of their current climatic range by 2080.” 

Here in southeast Arizona, many birds we know and love have been identified to be at risk by The Climate Report, including fairly common species like Swainson’s hawk, Green-tailed towhee, Rufous hummingbird, Gilded flicker, Gila woodpecker and the Western screech-owl. National Audubon Society’s models predict a “troubling situation on the breeding grounds” of the Green-tailed towhee. The model for this species predicts a “51-percent decrease in areas with proper climate . . . presumably as they are forced up in elevation and into smaller and smaller areas by drier and hotter conditions below.” Climate impacts will be felt differently for different species, depending upon their natural history, adaptability and the impacts of climate on vegetation and other food sources. By 2080, the Rufous hummingbird is projected to lose 100 percent of non-breeding range in the United States . . . models project that the hummer’s breeding range will also be disrupted and move north. How all this disruption affects this charismatic bird, and how changes to flower phenology factor in, remains to be seen.”  And just because climate conditions (i.e. temperature, precipitation, humidity, and seasonality) will shift into new areas does not necessarily mean birds associated with those climate variables will be able to quickly colonize and adapt to surviving there. Another factor to throw into the mix is that summer and winter ranges are predicted to be effected differently for some species.  According to the model predictions, the Western screech owl faces this climate conundrum:  “Altogether, the summer and winter ranges may become increasingly decoupled. In order to adapt the Western Screech-Owl may need to adopt a partially migratory life history—an uncertain prospect at best.”

Even bird species whose ranges are predicted to grow with climate change in the U.S. face unique problems.  For example, National Audubon reports, “the model projects huge gains for the Gila Woodpecker, with suitable climate in both winter and summer spreading all the way to peninsular Florida. If the species does in fact commence a vigorous range expansion, it will encounter and possibly hybridize with two congeners from which it is currently isolated: first the Golden-fronted and then the Red-bellied woodpecker.” The Gilded flicker faces a similar dilemma, “Although closely related, the two flickers are generally isolated today by geography and habitat, but they interbreed freely in a few Arizona locales where their ranges meet. As the Gilded Flicker, assisted by climate change, penetrates the range of the Northern Flicker, extensive interbreeding could ensue. Genetic “swamping” by one species, or mixing of both species’ gene pools, may be the unfortunate result.” 

Click here to learn 5 things you can do to help protect birds in the face of global warming.

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