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/

Amazon Inhales More Carbon than It Emits, NASA Finds

Old-growth Amazon tree canopy in Tapajós National Forest, Brazil. A new NASA study shows that the living trees in the undisturbed Amazon forest draw more carbon dioxide from the air than the forest’s dead trees emit. Image credit: NASA/JPL-Caltech

A new NASA-led study seven years in the making has confirmed that natural forests in the Amazon remove more carbon dioxide from the atmosphere than they emit, therefore reducing global warming. This finding resolves a long-standing debate about a key component of the overall carbon balance of the Amazon basin.

The Amazon’s carbon balance is a matter of life and death: living trees take carbon dioxide out of the air as they grow, and dead trees put the greenhouse gas back into the air as they decompose. The new study, published in Nature Communications on March 18, is the first to measure tree deaths caused by natural processes throughout the Amazon forest, even in remote areas where no data have been collected at ground level.

Fernando Espírito-Santo of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., lead author of the study, created new techniques to analyze satellite and other data. He found that each year, dead Amazonian trees emit an estimated 1.9 billion tons (1.7 billion metric tons) of carbon to the atmosphere. To compare this with Amazon carbon absorption, the researchers used censuses of forest growth and different modeling scenarios that accounted for uncertainties. In every scenario, carbon absorption by living trees outweighed emissions from the dead ones, indicating that the prevailing effect in natural forests of the Amazon is absorption.

Until now, scientists had only been able to estimate the Amazon’s carbon balance from limited observations in small forest areas called plots. On these plots, the forest removes more carbon than it emits, but the scientific community has been vigorously debating how well the plots represent all the natural processes in the huge Amazon region. That debate began with the discovery in the 1990s that large areas of the forest can be killed off by intense storms in events called blowdowns.

Espírito-Santo said that the idea for the study arose from a 2006 workshop where scientists from several nations came together to identify NASA satellite instruments that might help them better understand the carbon cycle of the Amazon. In the years since then, he worked with 21 coauthors in five nations to measure the carbon impacts of tree deaths in the Amazon from all natural causes — from large-area blowdowns to single trees that died of old age. He used airborne lidar data, satellite images, and a 10-year set of plot measurements collected by the University of Leeds, England, under the leadership of Emanuel Gloor and Oliver Phillips. He estimates that he himself spent a year-and-a-half doing fieldwork in the Amazon.

“It was a difficult and audacious study, and only Espírito-Santo’s dedication made it possible,” said Michael Keller, a research scientist at the U.S. Forest Service and co-author of the study.

Correlating satellite and airborne-instrument data with ground observations, Espírito-Santo and his colleagues devised methods to identify dead trees in different types of remotely sensed images. For example, fallen trees create a gap in the forest canopy that can be measured by lidar on research aircraft, and dead wood changes the colors in a satellite optical image. The researchers then scaled up their techniques so they could be applied to satellite and airborne data for parts of the Amazon with no corresponding ground data.

“We found that large natural disturbances — the sort not captured by plots — have only a tiny effect on carbon cycling throughout the Amazon,” said Sassan Saatchi of JPL, also a co-author. Each year, about two percent of the entire Amazon forest dies of natural causes. The researchers found that only about 0.1 percent of those deaths are caused by blowdowns.

This study looked only at natural processes in Amazonia, not at the results of human activities such as logging and deforestation, which vary widely and rapidly with changing political and social conditions.

The other institutions participating in the study are the University of New Hampshire, Durham; the Universities of Leeds and Nottingham, U.K.; Oxford University, U.K.; James Cook University, Cairns, Australia; U.S. Forest Service International Institute of Tropical Forestry, Puerto Rico; EMBRAPA Satellite Monitoring Center, Campinas, Brazil; National Institute for Research in Amazonia, Manaus, Brazil; EMBRAPA Eastern Amazonia, Santarém, Brazil; National Institute for Space Research (INPE), São José dos Campos, Brazil; the Missouri Botanical Garden, Oxapampa, Peru; and the Carnegie Institute for Science, Stanford, Calif.

NASA monitors Earth’s vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. NASA develops new ways to observe and study Earth’s interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

Source: http://www.jpl.nasa.gov/news/news.php?release=2014-084

For more information about NASA’s Earth science activities in 2014, visit: http://www.nasa.gov/earthrightnow

Big trees, like the old-growth forests they inhabit, are declining globally

Rhett Butler, mongabay.com 

Already on the decline, demise of giant trees may be hastened by global warming.

Already on the decline worldwide, big trees face a dire future due to habitat fragmentation, selective harvesting by loggers, exotic invaders, and the effects of climate change, warns an article published this week in New Scientist magazine. 
Reviewing research from forests around the world, William F. Laurance, an ecologist at James Cook University in Cairns, Australia, provides evidence of decline among the world’s “biggest and most magnificent” trees and details the range of threats they face. He says their demise will have substantial impacts on biodiversity and forest ecology, while worsening climate change.

“To persist, big trees need a safe place to live and long periods of stability,” he told mongabay.com via email. “But time and stability are becoming very rare commodities in our modern world.”

Giant trees offer critical habitat and forage for wildlife, while transpiring massive amounts of water through their leaves, contributing to local rainfall. Old trees also lock up massive amounts of carbon — in some forests they can account for up to a quarter of living biomass.

Dipterocarps are commonly targeted by loggers in Southeast Asia. This Dipterocarp was photographed in Borneo by Rhett A. Butler.

But their ability to sequester carbon and render other ecosystem services is threatened by human activities. Some of the world’s largest trees are particularly targeted by loggers. The oldest trees are among the most valuable and therefore the first to be cut in “virgin” forest areas.

Big trees are also sensitive to fragmentation, which exposes them to stronger winds and drier conditions. Laurance’s own work in the Amazon has shown substantial die-off of canopy giants in small forest fragments. Their susceptibility seems counter-intuitive given big trees’ life histories, which invariably include periods of drought and other stress.

“All around the tropics, big canopy and emergent trees are succumbing to strong droughts,” Laurance said. “That’s been a surprise to me and many other ecologists, because big, ancient trees would have had to survive many droughts in the past.”

Forest giants may suffer disproportionately from climate change, writes Laurance in New Scientist, highlighting research in La Selva, Costa Rica by David and Deborah Clark.

“Trees are probably getting a double-whammy when the thermometer rises,’ says David Clark. “During the day, their photosynthesis shuts down when it gets too warm, and at night they consume more energy because their metabolic rate increases, much as a reptile’s would do when it gets warmer.” With less energy being produced in warmer years and more being consumed just to survive, there is less energy available for growth.

The Clarks’ hypothesis, if correct, means tropical forests could shrink over time. The largest, oldest trees would progressively die off and tend not to be replaced. Alarmingly, this might trigger a positive feedback that could destabilize the climate: as older trees die, forests would release some of their stored carbon into the atmosphere, prompting a vicious circle of further warming, forest shrinkage and carbon emissions.

Giant Kapok tree in the Brazilian Amazon. Photo by Rhett A. Butler.

Laurance notes climate change is having less direct impacts on forests, including creating conditions for exotic pathogens to thrive. For example, pathogens such as Dutch Elm Disease, introduced by trade or circumstance, can devastate native forests.

All told, the outlook for big trees is not good, according to Laurance.

“The decline of big trees foretells a different world where ancient behemoths are replaced by short-lived pioneers and generalists that can grow anywhere, where forests store less carbon and sustain fewer dependent animals, where giant cathedral-like crowns become a thing of the past.”

Source: http://news.mongabay.com/2012/0126-big_trees.html

Climate Change Seen Posing Risk to Food Supplies

Josh Haner/The New York Times

A United Nations panel of scientists says that globally, rising temperatures will make it harder for crops to thrive.

By JUSTIN GILLIS

Climate change will pose sharp risks to the world’s food supply in coming decades, potentially undermining crop production and driving up prices at a time when the demand for food is expected to soar, scientists have found.

In a departure from an earlier assessment, the scientists concluded that rising temperatures will have some beneficial effects on crops in some places, but that globally they will make it harder for crops to thrive — perhaps reducing production over all by as much as 2 percent each decade for the rest of this century, compared with what it would be without climate change.

And, the scientists say, they are already seeing the harmful effects in some regions.

The warnings come in a leaked draft of a report under development by a United Nations panel, the Intergovernmental Panel on Climate Change. The document is not final and could change before it is released in March.

The report also finds other sweeping impacts from climate change already occurring across the planet, and warns that these are likely to intensify as human emissions of greenhouse gases continue to rise. The scientists describe a natural world in turmoil as plants and animals colonize new areas to escape rising temperatures, and warn that many could become extinct.

The warning on the food supply is the sharpest in tone the panel has issued. Its previous report, in 2007, was more hopeful. While it did warn of risks and potential losses in output, particularly in the tropics, that report found that gains in production at higher latitudes would most likely offset the losses and ensure an adequate global supply.

The new tone reflects a large body of research in recent years that has shown howsensitive crops appear to be to heat waves. The recent work also challenges previous assumptions about how much food production could increase in coming decades because of higher carbon dioxide levels in the atmosphere. The gas, though it is the main reason for global warming, also acts as a kind of fertilizer for plants.

The Intergovernmental Panel on Climate Change is the principal scientific body charged with reviewing and assessing climate science, then issuing reports about the risks to the world’s governments. Its main reports come out every five to six years. The group won the Nobel Peace Prize, along with Al Gore, in 2007 for its efforts.

Hundreds of billions of dollars are being spent every year to reduce emissions in response to past findings from the group, though many analysts have said these efforts are so far inadequate to head off drastic climatic changes later in the century.

On the food supply, the new report finds that benefits from global warming may be seen in some areas, like northern lands that are now marginal for food production. But it adds that over all, global warming could reduce agricultural production by as much as 2 percent each decade for the rest of this century.

During that period, demand is expected to rise as much as 14 percent each decade, the report found, as the world population is projected to grow to 9.6 billion in 2050, from 7.2 billion today, according to the United Nations, and as many of those people in developing countries acquire the money to eat richer diets.

Any shortfall would lead to rising food prices that would hit the world’s poor hardest, as has already occurred from price increases of recent years. Research has found that climate change, particularly severe heat waves, was a factor in those price spikes.

The agricultural risks “are greatest for tropical countries, given projected impacts that exceed adaptive capacity and higher poverty rates compared with temperate regions,” the draft report finds.

If the report proves to be correct about the effect on crops from climate change, global food demand might have to be met — if it can be met — by putting new land into production. That could entail chopping down large areas of forest, an action that would only accelerate climate change by sending substantial amounts of carbon dioxide into the air from the destruction of trees.

The report finds that efforts to adapt to climate change have already begun in many countries. President Obama signed an executive order on Friday to step up such efforts in the United States. But these efforts remain inadequate compared with the risks, the report says, and far more intensive — and expensive — adaptation plans are likely to be required in the future.

The document also finds that it is not too late for cuts in emissions to have a strong impact on the future risks of climate change, though the costs would be incurred in the next few decades and the main benefits would probably be seen in the late 21st century and beyond.

The leak of the new draft occurred on a blog hostile to the intergovernmental panel. In a brief interview, a spokesman for the panel, Jonathan Lynn, did not dispute the authenticity of the document.

“It’s a work in progress,” Mr. Lynn said. “It’s likely to change.”

Several scientists involved in drafting the document declined on Friday to speak publicly about it. In the Internet era, the group’s efforts to keep its drafts secret are proving to be a failure, and some of the scientists involved have called for a drafting process open to the public.

A report about the physical science of climate change leaked in August, then underwent only modest changes before its final release in Stockholm in late September. The new report covers the impact of climate change, efforts to adapt to it, and the vulnerability of human and natural systems.

A third report, analyzing potential ways to limit the rise of greenhouse gases, is due for release in Berlin in April.

A version of this article appears in print on November 2, 2013, on page A1 of the New York edition with the headline: Climate Change Seen Posing Risk to Food Supplies.

Source: http://www.nytimes.com/2013/11/02/science/earth/science-panel-warns-of-risks-to-food-supply-from-climate-change.html?