Severe impacts of climate change

Posted by Tim McDonnell, Jeremy Schulman, and James West

The impacts of climate change are likely to be “severe, pervasive, and irreversible,” the chair of the Intergovernmental Panel on Climate Change said Sunday night in Yokohama, Japan, as the world’s leading climate experts released a new survey of how our planet is likely to change in the near future, and what we can do about it.

Here’s what you need to know:

1. We’re already feeling the impacts of climate change. Glaciers are already shrinking, changing the courses of rivers and altering water supplies downstream. Species from grizzly bears to flowers have shifted their ranges and behavior. Wheat and maize yields may have dropped. But as climate impacts become more common and tangible, they’re being matched by an increasing global effort to learn how to live with them: The number of scientific studies on climate change impacts, vulnerability, and adaptation more than doubled between 2005, before the previous IPCC report, and 2010. Scientists and policymakers are “learning through doing, and evaluating what you’ve done,” said report contributor Kirstin Dow, a climate policy researcher at the University of South Carolina. “That’s one of the most important lessons to come out of here.”
2. Heat waves and wildfires are major threats in North America. Europe faces freshwater shortages, and Asia can expect more severe flooding from extreme storms. In North America, major threats include heat waves and wildfires, which can cause death and damage to ecosystems and property. The report names athletes and outdoor workers as particularly at risk from heat-related illnesses. As the graphic below shows, coastal flooding is also a key concern.

   
3. Globally, food sources will become unpredictable, even as population booms.Especially in poor countries, diminished crop production will likely lead to increased malnutrition, which already affects nearly 900 million people worldwide. Some of the world’s most important staples—maize, wheat, and rice—are at risk. The ocean will also be a less reliable source of food, with important fish resources in the tropics either moving north or going extinct, while ocean acidification eats away at shelled critters (like oysters) and coral. Shrinking supplies and rising prices will cause food insecurity, which can exacerbate preexisting social tensions and lead to conflict.
4. Coastal communities will increasingly get hammered by flooding and erosion. Tides are already rising in the US and around the world. As polar ice continues to melt and warm water expands, sea level rise will expose major metropolitan areas, military installations, farming regions, small island nations, and other ocean-side places to increased damage from hurricanes and other extreme storms. Sea level rise brings with it risks of “death, injury, ill-health, or disrupted livelihoods,” the report says.
5. We’ll see an increase in climate refugees and, possibly, climate-related violence.The report warns that both extreme weather events and longer-term changes in climate can lead to the displacement of vulnerable populations, especially in developing parts of the world. Climate change might also “indirectly increase” the risks of civil wars and international conflicts by exacerbating poverty and competition for resources.
6. Climate change is expected to make people less healthy. According to the report, we can expect climate change to have a negative impact on health in many parts of the world, especially poorer countries. Why? Heat waves and fires will cause injury, disease and death. Decreased food production will mean more malnutrition. And food- and water-borne diseases will make more people sick.
7. We don’t know how much adaptation is going to cost. The damage we’re doing to the planet means that human beings are going to have to adapt to the changing climate. But that costs money. Unfortunately, studies that estimate the global cost of climate adaptation “are characterized by shortcomings in data, methods, and coverage,” according to the IPCC. But from the “limited evidence” available, the report warns that there’s a “gap” between “global adaptation needs and the funds available.”
8. There’s still time to reduce the impacts of global warming…if we cut our emissions.Here’s the good news: The IPCC says that the impacts of climate change—and the costs of adaptation—will be “reduced substantially” if we cut our emissions of greenhouse gases.

Source: http://climatedesk.org/2014/03/if-this-terrifying-report-doesnt-wake-you-up-to-the-realities-of-what-were-doing-to-this-planet-what-will/

Alpine grazing: does it reduce blazing?

A large body of evidence shows that it does not

Synthesis by Dr Richard Williams, CSIRO Tropical Ecosystems Research Centre, and Imogen Fraser, The University of Melbourne

There have been recent calls by the Victorian Mountain Cattlemen’s Association to re-introduce cattle grazing in the Victorian Alpine National Park to reduce fire risk.

Strong evidence gathered over many years convincingly shows that cattle grazing in the Australian high country does not reduce the risk of fire.

Reintroduction of cattle to the Alpine National Park is extremely unlikely to reduce fire risk, but is highly likely to damage sensitive alpine soils and vegetation.

The Victorian Mountain Cattlemen’s Association has called for the re-introduction of cattle grazing in the Victorian Alpine National Park to reduce fire risk, based on their view that ‘alpine grazing reduces blazing’. However, a substantial body of peer-reviewed scientific evidence indicates that alpine grazing does not reduce fire risk.

Cattle on the Bogong High Plains following the 2003 fires. Photo Carl-Henrik Wahren

Detailed studies of the 2003 and 2007 fires in the Victorian Alpine National Park showed that cattle grazing had little or no effect on occurrence and/or severity of fire in the alpine vegetation above treeline, and in the surrounding subalpine woodland and montane forest. Flammability depended largely on vegetation type. For example, the 2003 fires on the Bogong High Plains burnt 87% of closed heathland and 59% of open heathland, but only 13% of grassland; grazing did not reduce the incidence of fire in any of these vegetation types.

Cattle graze selectively and this partly explains why grazing had little effect on the patterns of burning. On the Bogong High Plains detailed studies have shown that cattle prefer to graze on the grasses and herbs of the more open vegetation types such as grassland and open heathland, and avoid eating the tall shrubs of the closed heathland. Long-term monitoring on the Bogong High Plains for over 50 years has shown that cattle grazing has not reduced the cover of tall shrubs that dominate the most flammable vegetation – closed heathland.

Victoria’s alpine vegetation is resilient to large fires and there is no apparent conservation imperative to mitigate the extent or severity of large fires. Livestock grazing, on the other hand, has well-documented negative impacts on the conservation values of Australia’s rare alpine and subalpine ecosystems. There is therefore no scientific basis to support the re-introduction of cattle grazing to reduce fire risk in Australian alpine and subalpine ecosystems.

Hot Topic Lead Author:
Name: Dr Dick Williams
Email: dickwilliams1955@gmail.com
Phone: 61-404958679

Original source and access to all the papers related here: https://www.ecolsoc.org.au/node/6540

The Ecological Importance of California’s Rim Fire

Large, intense fires have always been a natural part of fire regimes in Sierra Nevada forests BY CHAD HANSON

Since the Rim fire began in the central Sierra Nevada on August 17, there has been a steady stream of fearful, hyperbolic, and misinformed reporting in much of the media. The fire, which is currently 188,000 acres in size and covers portions of the Stanislaus National Forest and the northwestern corner of Yosemite National Park, has been consistently described as “catastrophic”, “destructive”, and “devastating.” One story featured a quote from a local man who said he expected “nothing to be left”. However, if we can, for a moment, set aside the fear, the panic, and the decades of misunderstanding about wildland fires in our forests, it turns out that the facts differ dramatically from the popular misconceptions. The Rim fire is a good thing for the health of the forest ecosystem. It is not devastation, or loss. It is ecological restoration.

Photo courtesy USDAPatches of high-intensity fire, wherein most or all trees are killed, creates “snag forest habitat” which is the rarest and one of the most ecologically important forest habitat types in the entire Sierra Nevada.

What relatively few people in the general public understand at present is that large, intense fires have always been a natural part of fire regimes in Sierra Nevada forests. Patches of high-intensity fire, wherein most or all trees are killed, creates “snag forest habitat,” which is the rarest, and one of the most ecologically important, forest habitat types in the entire Sierra Nevada. Contrary to common myths, even when forest fires burn hottest, only a tiny proportion of the aboveground biomass is actually consumed (typically less than 3 percent). Habitat is not lost. Far from it. Instead, mature forest is transformed into “snag forest”, which is abundant in standing fire-killed trees, or “snags,” patches of native fire-following shrubs, downed logs, colorful flowers, and dense pockets of natural conifer regeneration.

This forest rejuvenation begins in the first spring after the fire. Native wood-boring beetles rapidly colonize burn areas, detecting the fires from dozens of miles away through infrared receptors that these species have evolved over millennia, in a long relationship with fire. The beetles bore under the bark of standing snags and lay their eggs, and the larvae feed and develop there. Woodpecker species, such as the rare and imperiled black-backed woodpecker (currently proposed for listing under the Endangered Species Act), depend upon snag forest habitat and wood-boring beetles for survival.

One black-backed woodpecker eats about 13,500 beetle larvae every year — and that generally requires at least 100 to 200 standing dead trees per acre. Black-backed woodpeckers, which are naturally camouflaged against the charred bark of a fire-killed tree, are a keystone species, and they excavate a new nest cavity every year, even when they stay in the same territory. This creates homes for numerous secondary cavity-nesting species, like the mountain bluebird (and, occasionally, squirrels and even martens), that cannot excavate their own nest cavities. The native flowering shrubs that germinate after fire attract many species of flying insects, which provide food for flycatchers and bats; and the shrubs, new conifer growth, and downed logs provide excellent habitat for small mammals. This, in turn, attracts raptors, like the California spotted owl and northern goshawk, which nest and roost mainly in the low/moderate-intensity fire areas, or in adjacent unburned forest, but actively forage in the snag forest habitat patches created by high-intensity fire — a sort of “bedroom and kitchen” effect. Deer thrive on the new growth, black bears forage happily on the rich source of berries, grubs, and small mammals in snag forest habitat, and even rare carnivores like the Pacific fisher actively hunt for small mammals in this post-fire habitat.

Photo by Rachel FazioThe imperiled black-backed woodpecker, a forest management indicator species, has been reduced to a mere several hundred pairs in the Sierra Nevada due to fire suppression, post-fire logging, and commercial thinning of forests.

In fact, every scientific study that has been conducted in large, intense fires in the Sierra Nevada has found that the big patches of snag forest habitat support levels of native biodiversity and total wildlife abundance that are equal to or (in most cases) higher than old-growth forest. This has been found in the Donner fire of 1960, the Manter and Storrie fires of 2000, the McNally fire of 2002, and the Moonlight fire of 2007, to name a few. Wildlife abundance in snag forest increases up to about 25 or 30 years after fire, and then declines as snag forest is replaced by a new stand of forest (increasing again, several decades later, after the new stand becomes old forest). The woodpeckers, like the black-backed woodpecker, thrive for 7 to 10 years after fire generally, and then must move on to find a new fire, as their beetle larvae prey begins to dwindle. Flycatchers and other birds increase after 10 years post-fire, and continue to increase for another two decades. Thus, snag forest habitat is ephemeral, and native biodiversity in the Sierra Nevada depends upon a constantly replenished supply of new fires.

It would surprise most people to learn that snag forest habitat is far rarer in the Sierra Nevada than old-growth forest. There are about 1.2 million acres of old-growth forest in the Sierra, but less than 400,000 acres of snag forest habitat, even after including the Rim fire to date. This is due to fire suppression, which has, over decades, substantially reduced the average annual amount of high-intensity fire relative to historic levels, according to multiple studies. Because of this, and the combined impact of extensive post-fire commercial logging on national forest lands and private lands, we have far less snag forest habitat now than we had in the early twentieth century, and before. This has put numerous wildlife species at risk. These are species that have evolved to depend upon the many habitat features in snag forest — habitat that cannot be created by any other means. Further, high-intensity fire is not increasing currently, according to most studies (and contrary to widespread assumptions), and our forests are getting wetter, not drier (according to every study that has empirically investigated this question), so we cannot afford to be cavalier and assume that there will be more fire in the future, despite fire suppression efforts.  We will need to purposefully allow more fires to burn, especially in the more remote forests.

The black-backed woodpecker, for example, has been reduced to a mere several hundred pairs in the Sierra Nevada due to fire suppression, post-fire logging, and commercial thinning of forests, creating a significant risk of future extinction unless forest management policies change, and unless forest plans on our national forests include protections (which they currently do not). This species is a “management indicator species”, or bellwether, for the entire group of species associated with snag forest habitat. As the black-backed woodpecker goes, so too do many other species, including some that we probably don’t yet know are in trouble. The Rim fire has created valuable snag forest habitat in the area in which it was needed most in the Sierra Nevada: the western slope of the central portion of the range. Even the Forest Service’s own scientists have acknowledged that the levels of high-intensity fire in this area are unnaturally low, and need to be increased. In fact, the last moderately significant fires in this area occurred about a decade ago, and there was a substantial risk that a 200-mile gap in black-backed woodpeckers populations was about to develop, which is not a good sign from a conservation biology standpoint. The Rim fire has helped this situation, but we still have far too little snag forest habitat in the Sierra Nevada, and no protections from the ecological devastation of post-fire logging.

Photo by Doug BevingtonThe big patches of snag forest habitat support levels of native biodiversity and total wildlife abundance that are equal to or (in most cases) higher than old-growth forest.

Recent scientific studies have caused scientists to substantially revise previous assumptions about historic fire regimes and forest structure. We now know that Sierra Nevada forests, including ponderosa pine and mixed-conifer forests, were not homogenously “open and parklike” with only low-intensity fire. Instead, many lines of evidence, and many published studies, show that these areas were often very dense, and were dominated by mixed-intensity fire, with high-intensity fire proportions ranging generally from 15 percent to more than 50 percent, depending upon the fire and area. Numerous historic sources, and reconstructions, document that large high-intensity fire patches did in fact occur prior to fire suppression and logging. Often these patches were hundreds of acres in size, and occasionally they were thousands — even tens of thousands — of acres. So, there is no ecological reason to fear or lament fires like the Rim fire, especially in an era of ongoing fire deficit.

Most fires, of course, are much smaller, and less intense than the Rim fire, including the other fires occurring this year. Over the past quarter-century fires in the Sierra Nevada have been dominated on average by low/moderate-intensity effects, including in the areas that have not burned in several decades. But, after decades of fear-inducing, taxpayer-subsidized, anti-fire propaganda from the US Forest Service, it is relatively easier for many to accept smaller, less intense fires, and more challenging to appreciate big fires like the Rim fire. However, if we are to manage forests for ecological integrity, and maintain the full range of native wildlife species on the landscape, it is a challenge that we must embrace.

Encouragingly, the previous assumption about a tension between the restoration of more fire in our forests and home protection has proven to be false. Every study that has investigated this issue has found that the only way to effectively protect homes is to reduce combustible brush in “defensible space” within 100 to 200 feet of individual homes. Current forest management policy on national forest lands, unfortunately, remains heavily focused not only on suppressing fires in remote wildlands far from homes, but also on intensive mechanical “thinning” projects — which typically involve the commercial removal of upwards of 80 percent of the trees, including mature trees and often old-growth trees —that are mostly a long distance from homes. This not only diverts scarce resources away from home protection, but also gives homeowners a false sense of security because a federal agency has implied, incorrectly, that they are now protected from fire — a context that puts homes further at risk.

The new scientific data is telling us that we need not fear fire in our forests. Fire is doing important and beneficial ecological work, and we need more of it, including the occasional large, intense fires. Nor do we need to balance home protection with the restoration of fire’s role in our forests. The two are not in conflict. We do, however, need to muster the courage to transcend our fears and outdated assumptions about fire. Our forest ecosystems will be better for it.

Chad Hanson
Chad Hanson, the director of the John Muir Project (JMP) of Earth Island Institute, has a Ph.D. in ecology from the University of California at Davis, and focuses his research on forest and fire ecology in the Sierra Nevada. He can be reached at cthanson1@gmail.com, or visit JMP’s website at www.johnmuirproject.org for more information, and for citations to specific studies pertaining to the points made in this article.

Source: http://www.earthisland.org/journal/index.php/elist/eListRead/the_ecological_importance_of_californias_rim_fire/

On Boreal forests, fires and natural processes

Charcoal records reveal that far northern wildfires have doubled in frequency recently

By Stephanie Paige Ogburn and ClimateWire

Image: Flickr/Drew Brayshaw

 

Alaska is burning more than it has in the past 10,000 years.

That’s the finding of research released yesterday in the journal Proceedings of the National Academy of Sciences.

The study analyzed charcoal found in sediment cores from 14 lakes in the Yukon Flats region of the state to determine the frequency of past fires.

Over the last 3,000 years, the average fire frequency in the area was about 10 fires per thousand years.

In the last 50 years, the fire frequency has nearly doubled, up to 20 every thousand years, or one fire every 50 years.

Climate scientists care about what might happen in boreal forests because they cover 10 percent of land surface and store a lot of carbon in their soil, said Ryan Kelly, an ecologist and doctoral candidate at the University of Illinois who was lead author of the study.

“It is a significant player in the global carbon cycle,” Kelly said. “When the forests burn, the carbon goes into the atmosphere. If they burn more frequently, they are releasing more carbon, and storing less.”

The researchers were particularly interested in comparing fire frequency from the recent past with that of a period called the Medieval Climate Anomaly, when conditions were warm and dry, similar to recent decades.

Forest may self-regulate
When they did this, they found a surprising—and possibly hopeful—result. They noted that fire frequency was also high about 1,000 years ago, during the anomaly.

But pollen records the researchers analyzed show that during that time of increased fire, the forest responded by changing the vegetation that regrew after the fires. The trees shifted from evergreen to deciduous. The deciduous trees, like aspen and birch, did not burn as easily, and this slowed down the fire frequency.

“So that’s really interesting to us as ecologists, because it is a mechanism by which ecosystems are kind of regulating themselves,” he said.

Jennifer Marlon, a scientist at the Yale School of Forestry and Environmental Studies who studies wildfires and climate change, said the study was unique because it used a lot of records from one location. “Their conclusions were very robust because of the scope and scale of the study,” Marlon said.

The findings were also unique because the researchers were able to so closely link historical records with what is happening in the present and what might happen in the future, she said. “Using the paleo records, long historical records like this, it is fairly rare to be able to connect it so closely to what is happening today.”

The fact that the number of forest fires in a past warm period was reduced by the regrowth of different trees might offer some hope for reduced fire frequency in the future, even though the frequency in recent decades has been high, Kelly said.

This idea could be validated by modeling studies. It also might play out in the next few decades, as scientists watch, Kelly said.

Whether the regulating mechanism of deciduous trees kicks in could depend on how much that region warms, said Philip Higuera, an ecologist from the University of Idaho and a co-author on the study.

“To me, the key thing that that hangs on is how much we turn that temperature knob up,” said Higuera.

Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500

Source: http://www.scientificamerican.com/article.cfm?id=boreal-forests-burning-more-now-than-any-time-in-past-10000-years