The Insidious Side of Climate Change

If you think climate change just means hotter summers in California, think again. The writer of this week’s guest post argues that we’ll all “feel the heat” in myriad ways, both obvious and subtle.

Climate and Nature
by Anthony Barnosky

Some impacts of climate change in California are pretty obvious, things like rising sea level submerging large parts of the San Francisco Bay region, or drought cutting into our water supplies.  Less obvious, but every bit as important, are impacts on something you probably don’t even know you have: your relationship with nature.

One part of that relationship is the concept of “ecosystem services;” the direct benefits you get from nature.  California’s Climate Action Team highlighted some of the state’s ecosystem services in their recent report.  Examples include the ski trip you may have taken this winter, the salmon fillet you may have bought at the grocery store, or surprisingly, even your hamburger.

barnosky_snowfunSnow will be less, soggier, at higher elevations, and on the ground for fewer days of the winter, melting some of the $500 million-per-year revenues of the ski industry–not to mention melting your favorite ski run.  Altered river dynamics and temperatures will almost certainly cut into the state’s $33-million-per-year salmon industry. Climate-caused loss of forage means that in 2070 California’s cattle ranchers will be losing up to $92 million in comparison to today’s markets, which means higher beef prices at the grocery store.  Combined, the losses in these ecosystem services likely will cost the state’s already suffering economy well over a hundred million dollars per year as we move into the next few decades. And those are just three of many ecosystem services that will be affected.

A second part of your relationship to nature is the species around you, that is to say, biodiversity. Simply put, biodiversity is which species live in a place, and the extent to which those species are rare or common.  In general, biodiversity means more productive and healthier ecosystems, which translates as more benefits to humans that inhabit those areas.  As it turns out, California is a globally recognized biodiversity hotspot, unique in the world.  But biodiversity losses from global warming promise to be severe: one study predicts that two-thirds of the 2387 plant species found only in the state will lose 80% of their range within the century.

barnosky_icylakeThe third part of your relationship to nature is how it makes you feel.  There’s no question: you can’t get the same feeling you get looking at a giant redwood anywhere but in a redwood forest.   Among species that may have little or no suitable climate left in California, however, are its coastal redwoods and sequoias.

Such impacts of climate change on nature are not confined to California.   Many other reports indicate that global warming is redefining our relationship to nature worldwide.  As with other impacts, this one can be partially mitigated by reducing greenhouse gas emissions immediately, but also will require some new management strategies for preserving nature in the age of global warming.  California, in particular, has a lot to lose.

Anthony D. Barnosky is a Professor of Integrative Biology at the University of California, Berkeley and author of the recently published Heatstroke: Nature in an Age of Global Warming. You can read more on this topic in his blog. Photos by the author.

Barnosky is scheduled to appear Saturday as part of Berkeley’s “Cal Day” activities. His talk is scheduled for noon at the Valley Life Sciences Bldg, Room 2060, followed by a book-signing at the T-Rex (which is hard to miss).

Climate Debate Runs Hot and Cold

We see occasional references in our discussions here to a “cooling phase” over the past decade or so. It’s often evoked in arguments against the case for global warming. Of course, in the centuries-long span of the Earth’s climate patterns, a decade or so is a mere blip on the screen.

Now a climatologist at Lawrence Berkeley National Lab has co-authored a paper that warns against using “periods of a decade or two” to argue the case one way or the other (we also often hear people use temperature data from recent hotter years as evidence for global warming).

Andrew Revkin summarizes the findings in his blog for the New York Times.

Wehner works in the Computational Research Division at LBNL and co-authored the paper with NOAA scientist David Easterling of the National Climatic Data Center, in Ashville, NC. Easterling wrote the Center’s FAQ page on global warming, in which he includes this answer to the question of whether the global climate is warming:

Global surface temperatures have increased about 0.74°C (plus or minus 0.18°C) since the late-19th century, and the linear trend for the past 50 years of 0.13°C (plus or minus 0.03°C) per decade is nearly twice that for the past 100 years. The warming has not been globally uniform. Some areas (including parts of the southeastern U.S. and parts of the North Atlantic) have, in fact, cooled slightly over the last century. The recent warmth has been greatest over North America and Eurasia between 40 and 70°N. Lastly, seven of the eight warmest years on record have occurred since 2001 and the 10 warmest years have all occurred since 1995.”

As for the geographic fluctuations, Robert Bornstein of San Jose State has produced data showing a general cooling trend along the California coast over the past 30 or 40 years. But he’s quick to point out that the anomaly is most likely a result of, not an argument against the broader global warming trend.

Small Mammals on the Move in a Warming Yosemite

Over the last century, small mammals in Yosemite National Park have been on the move.  A recent study published in today’s issue of Science finds that as temperatures have warmed (a 3-degree Celcius increase in the park’s night-time low temperature) and Sierra glaciers have continued to melt, small mammals like mice, shrews, and chipmunks have moved to higher elevations or reduced their ranges in response to the climate.As part of the Grinnell Resurvey Project, a team from UC Berkeley’s Museum of Vertebrate Zoology headed up by professor Craig Moritz recently documented these changes in Yosemite by conducting a survey of the animal populations and comparing their data with an extensive data set collected in the same locations by field biologist Joseph Grinnell in the early 20th century.Of the 28 small mammals observed in the study, half had expanded their range upslope by more than 1,600 feet.

Since the higher up you are, the cooler the temperatures tend to be, recent research suggests that the mammals already living at high elevations may eventually face “mountaintop extinctions,” as they run out of room to climb higher if temperatures continue to rise. For example, the alpine chipmunk, which in 1918 was common at 7,800 feet, was recently nowhere to be found below 9,600 feet, according to the study.

Scientists acknowledge that changes in populations and animal communities are natural, but, Moritz says, what is less common is the speed with which these changes occured.