Category Archives: Nature

Changing cloud cover accelerates global warming


Regions where cloud cover has increased [blue] or decreased [orange] based on observations and models - Image: Joel Norris

Regions where cloud cover has increased [blue] or decreased [orange] based on observations and models – Image: Joel Norris

More bad news for our children and their children comes from a new study that reveals yet another accelerant triggering the fires of global warming.

The greenhouse gases that are the main culprit in raising global temperatures are changing the patterns of the world’s clouds, and the shifts bode ill for the future.

From the Scripps Institution of Oceanography at University of California San Diego:

A Scripps Institution of Oceanography at University of California San Diego-led research team analyzing satellite cloud records has found that the cloudy storm tracks on Earth are moving toward the poles and subtropical dry zones are expanding. Cloud tops are also moving higher in the atmosphere.

The record confirms computer climate models that have predicted these changes to have taken place during the past several decades as a consequence of the accumulation of societally generated greenhouse gases in the atmosphere.

“What this paper brings to the table is the first credible demonstration that the cloud changes we expect from climate models and theory are currently happening,” said study lead author Joel Norris, a climate researcher at Scripps.

With the simultaneous roles clouds play in cooling and heating the planet – reflecting solar radiation back to space but also trapping solar energy in their structures – clouds are among the most important variables in climate.

Their complex behavior has been one of the biggest areas of uncertainty for scientists attempting to understand current climate and forecast future trends.

Inconsistent satellite imaging of clouds over the decades has been a hindrance to improving scientists’ understanding. Records of cloudiness from satellites originally designed to monitor weather are prone to spurious trends related to changes in satellite orbit, instrument calibration, degradation of sensors over time, and other factors.

When the researchers removed such artifacts from the record, the data exhibited large-scale patterns of cloud change between the 1980s and 2000s that are consistent with climate model predictions for that time period, including poleward retreat of mid-latitude storm tracks, expansion of subtropical dry zones, and increasing height of the highest cloud tops. These cloud changes enhance absorption of solar radiation by the earth and reduce emission of thermal radiation to space. This exacerbates global warming caused by increasing greenhouse gas concentrations.

The researchers drew from several independent corrected satellite records in their analysis. They concluded that the behavior of clouds they observed is consistent with a human-caused increase in greenhouse gas concentrations and a planet-wide recovery from two major volcanic eruptions, the 1982 El Chichón eruption in Mexico and the 1991 eruption of Mt. Pinatubo in the Philippines. Aerosols ejected from those eruptions had a net cooling effect on the planet for several years after they took place.

Barring another volcanic event of this sort, the scientists expect the cloud trends to continue in the future as the planet continues to warm due to increasing greenhouse gas concentrations.

The study, “Evidence for Climate Change in the Satellite Cloud Record” [$32 to read for non-subscribers to the $199-a-year journal], appears July 11 in the journal Nature. Researchers from University of California Riverside, Lawrence Livermore National Laboratory, and Colorado State University are co-authors. NOAA, the U.S. Department of Energy Office of Science, and NASA supported the research.

Somehow a certain song seems in order:

Joni Mitchell — Both Sides Now

El Niño aftermath brings specter of starvation


And those most deeply impacted are children in some of the world’s poorest countries.

We begin with a map from the UNICEF Briefing Papers It’s not over, El Niño’s impact on children:

EL NIÑO AND LA NIÑA RAINFALL: El Niño and La Niña conditions in the tropical Pacific are known to shift rainfall patterns in many different parts of the world. Although they vary somewhat from one to the next, the strongest shifts remain fairly consistent in the regions and seasons shown.

EL NIÑO AND LA NIÑA RAINFALL: El Niño and La Niña conditions in the tropical Pacific are known to shift rainfall patterns in many different parts of the world. Although they vary somewhat from one to the next, the strongest shifts remain fairly consistent in the regions and seasons shown.

And the story, via the United Nations News Center:

While the 2015-2016 El Niño – one of the strongest on record – has ended, its devastating impact on children is worsening, as hunger, malnutrition and disease continue to increase following the severe droughts and floods spawned by the event, a new report from the United Nations Children’s Fund (UNICEF) revealed today.

Making matters worse, there is a strong chance La Niña – El Niño’s flip side – could strike at some stage this year, further exacerbating a severe humanitarian crisis that is affecting millions of children in some of the most vulnerable communities, UNICEF said in a report It’s not over – El Niño’s impact on children.

El Niño is the term used to describe the warming of the central to eastern tropical Pacific that occurs, on average, every three to seven years. It raises sea surface temperatures and impacts weather systems around the globe so that some places receive more rain while others receive none at all, often in a reversal of their usual weather pattern.

While El Niño, and its counterpart La Niña, occur cyclically, in recent years, mainly due to the effects of global climate change, extreme weather events associated with these phenomena – such as droughts and floods – have increased in frequency and severity, according to UN agencies.

“Millions of children and their communities need support in order to survive. They need help to prepare for the eventuality La Niña will exacerbate the humanitarian crisis. And they need help to step up disaster risk reduction and adaptation to climate change, which is causing more intense and more frequent extreme weather events,” said UNICEF’s Director of Emergency Programs, Afshan Khan.

There’s more, after the jump. . . Continue reading

Headline of the day II: Crimes of our own greed


From Agence France Presse:

Bornean orangutan, whale shark sliding towards extinction: conservationists

The Bornean orangutan is on the verge of extinction, a top conservationist body said Friday, also warning that the world’s biggest fish, the whale shark, and a hammerhead shark species were endangered

Climate change linked to major plant life shifts


Following up on the previous post about global warming impacts on fauna in the American West, two studies on impacts on flora, both on the land and under the sea.

First, from the U.S. Department of Energy’s Office of Science:

Image courtesy of Denise Krebs (Flickr) via a Creative Commons License. A mixed-grass community prairie in Iowa.

Image courtesy of Denise Krebs (Flickr) via a Creative Commons License. A mixed-grass community prairie in Iowa.

The Science

Climate controls vegetation distribution across Earth, with some vegetation types being more vulnerable to climate change and others more resistant. Because resistance and resilience can influence ecosystem stability and determine how communities and ecosystems respond to climate change, evaluating the potential for resistance in future prairies and other ecosystems is important. Led by researchers from Wyoming, a team found that elevated carbon dioxide levels suppress the dominant plant species in a northern U.S. Great Plains mixed-grass prairie, creating a less diverse community.

The Impact

The economic value of many grasslands depends largely on plant community composition and the relative abundance of key forage species. Findings from this research have implications for managing native grasslands in the face of changing climate and its accompanying precipitation variations.

Summary

A large field experiment conducted in a northern U.S. Great Plains mixed-grass prairie was led by a research team from the University of Wyoming. The scientists tested the effects of elevated carbon dioxide, warming, and summer irrigation on plant community structure and productivity. This study sought to understand changes to stability in the community’s composition and to biomass production. Investigators found that (1) the independent effects of carbon dioxide and warming depend on interannual variation in precipitation and (2) the effects of elevated carbon dioxide are not limited to water saving because they differ from those of irrigation. Also shown was that production in this prairie ecosystem is not only relatively resistant to interannual variation in precipitation, but also rendered more stable under elevated carbon dioxide conditions. This increase in production stability resulted from altered community dominance patterns; that is, community evenness increases as dominant species decrease in biomass under elevated carbon dioxide.

And the impacts on ocean plant life from the University of New South Wales:

 Bleached seaweed. Image: Alexandra Campbell


Bleached seaweed. Image: Alexandra Campbell

A variety of normally harmless bacteria can cause bleaching disease in seaweeds when the seaweeds become stressed by high water temperatures, UNSW researchers have discovered.

Seaweeds are the “trees” of the ocean, providing vital habitat, food and shelter for many species of fish and other coastal marine organism, such as crayfish and abalone.

Read the rest, after the jump. . .

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Maps of the day: Bird habitats and climate change


Depending on the bird species, projected changes in the ranges between 2009 and 2099 indicate both contraction (red) and expansion (green). Blue areas shown are areas where ranges continue to persist, while tan areas are places that were not suitable in either time period.

Depending on the bird species, projected changes in the ranges between 2009 and 2099 indicate both contraction (red) and expansion (green). Blue areas shown are areas where ranges continue to persist, while tan areas are places that were not suitable in either time period.

In addition to major changes in the physical environment, rising temperatures will bring dramatic shifts in the habitats of countless species, most notably in the semi-arid American West, esnl‘s own habitat for the last six decades.

From the U.S. Geological Survey:

With temperatures projected to increase approximately 6 degrees Fahrenheit in the Southwestern United States and precipitation projected to decrease between 5 and 20 percent this century, habitat for some bird and reptile species may be negatively affected, according to new research [open access] by scientists from the U.S. Geological Survey, University of New Mexico and Northern Arizona University.

“This study identified better tools and strategies to conserve and sustain wildlife habitats in the Western U.S. using specific information about climate change consequences from models the authors developed,” said Dr. Charles van Riper III, senior research ecologist with the USGS and report co-author. “In conducting this study, we coupled existing global climate change models with newly developed species distribution models to estimate future losses and gains of Southwestern bird and reptile species.”

“Resource managers need scientific products and tools to inform planning and decisions under climate change and habitat alteration,” said Dr. Stephen Jackson, director of the Department of the Interior’s Southwest Climate Science Center. “This study will help managers assess the potential consequences of climate change for bird and reptile species, identify vulnerable species and populations and develop robust plans for climate adaptation.”

Fifteen species of birds and 16 reptile species comprised the study, including well-known species such as the Gila monster, horned lizard, chuckwalla, Sonoran desert tortoise, pinyon jay, pygmy nuthatch, sage thrasher and black-throated sparrow.

Projected changes in bird and reptile ranges varied widely among species:

  • One-third of the ranges are predicted to expand, while two-thirds are predicted to contract.
  • Several reptile species are projected to lose between 25 and 72 percent of their range, including the Gila spotted whiptail, Arizona black rattlesnake and ornate box turtle.
  • Numerous bird species are projected to lose between 78 and 85 percent of their range, including Williamson’s sapsucker, sage thrasher, red-naped sapsucker and pygmy nuthatch.

There’s more, after the jump. . . Continue reading

Arctic sea ice levels continue record decline


First, two graphics from the National Snow and Ice Data Center:

Figure 1. Arctic sea ice extent for June 2016 was 10.60 million square kilometers (4.09 million square miles). The magenta line shows the 1981 to 2010 median extent for that month. The black cross indicates the geographic North Pole.

Figure 1. Arctic sea ice extent for June 2016 was 10.60 million square kilometers (4.09 million square miles). The magenta line shows the 1981 to 2010 median extent for that month. The black cross indicates the geographic North Pole.

Figure 2. The graph above shows Arctic sea ice extent as of July 5, 2016, along with daily ice extent data for four previous years. 2016 is shown in blue, 2015 in green, 2014 in orange, 2013 in brown, and 2012 in purple. The 1981 to 2010 average is in dark gray. The gray area around the average line shows the two standard deviation range of the data.

Figure 2. The graph above shows Arctic sea ice extent as of July 5, 2016, along with daily ice extent data for four previous years. 2016 is shown in blue, 2015 in green, 2014 in orange, 2013 in brown, and 2012 in purple. The 1981 to 2010 average is in dark gray. The gray area around the average line shows the two standard deviation range of the data.

And the findings, from the Center’s report:

June set another satellite-era record low for average sea ice extent, despite slower than average rates of ice loss. The slow rate of ice loss reflects the prevailing atmospheric pattern, with low pressure centered over the central Arctic Ocean and lower than average temperatures over the Beaufort Sea.

Arctic sea ice extent during June 2016 averaged 10.60 million square kilometers (4.09 million square miles), the lowest in the satellite record for the month. So far, March is the only month in 2016 that has not set a new record low for Arctic-wide sea ice extent (March 2016 was second lowest, just above 2015). June extent was 260,000 square kilometers (100,000 square miles) below the previous record set in 2010, and 1.36 million square kilometers (525,000 square miles) below the 1981 to 2010 long-term average.

Sea ice extent remains below average in the Kara and Barents seas, as it has throughout the winter and spring. Despite lower than average temperatures over the Beaufort Sea, sea ice extent there remains below average, and was the second lowest extent for the month of June during the satellite data record.

The average rate of ice loss during June 2016 was 56,900 square kilometers (22,000 square miles) per day, but was marked by two distinct regimes. First, there was a period of slow loss during June 4 to 14 of only 37,000 square kilometers (14,000 square miles) per day. This was followed by above average rates (74,000 square kilometers, or 29,000 square miles) for the rest of the month. For the month as a whole, the rate of loss was close to average (53,600 square kilometers per day). The slow ice loss during early June was a result of a significant change in the atmospheric circulation. May was characterized by high surface pressure over the Arctic Ocean, a basic pattern that has held since the beginning of the year. However, June saw a marked shift to low pressure over the central Arctic Ocean. This type of pattern is known to inhibit ice loss. A low pressure pattern is associated with more cloud cover, limiting the input of solar energy to the surface, as well as generally below average air temperatures. However, in June 2016, it was only in the Beaufort Sea where air temperatures at the 925 hPa level were distinctly below average (about 2° Celsius below average, or 4° Fahrenheit). The change in circulation also shifted the pattern of ice motion. In general, winds associated with such a low pressure pattern will tend to spread the ice out (that is, cause the ice to diverge).

Climate change, drought cut Amazonia carbon sink


A feedback loops can trigger a cascading series of events, in which one step leads to another, feeding back to the original change in an acceleration of changes.

Science has arrived at a consensus that the release of greater amounts of carbon into the atmosphere leads to an increase in global temperatures.

And now comes the real possibility that climate change itself can accelerate atmospheric carbon dioxide levels by destroying the forest that serve s natural carbon sinks.

That’s one of the conclusions from a sobering new study of changes in the Amazon Basin, perhaps the world’s greatest natural carbon sink.

From the University of Exeter:

A recent drought completely shut down the Amazon Basin’s carbon sink, by killing trees and slowing their growth, a ground-breaking study led by researchers at the Universities of Exeter and Leeds has found.

Previous research has suggested that the Amazon – the most extensive tropical forest on Earth and one of the “green lungs” of the planet – may be gradually losing its capacity to take carbon from the atmosphere. This new study, the most extensive land-based study of the effect of drought on Amazonian rainforests to date, paints a more complex picture, with forests responding dynamically to an increasingly variable climate.

The study made use of two large-scale droughts occurring just five years apart, in 2005 and 2010, to improve understanding of how drought affects tree growth, and therefore the rate of uptake by trees of carbon dioxide from the atmosphere.

In the first basin-wide study of the impact of the 2010 drought and its interaction with previous droughts, the international team of researchers found that tree growth was markedly slowed by drought across the vast forests of the Amazon.

By using long-term measurements from the RAINFOR network spanning nearly a hundred locations across the Amazon Basin, the team was able to examine the responses of trees. In both the first drought and the second the Amazon temporarily lost biomass. But while both droughts killed many trees, the 2010 drought also had the effect of slowing the growth rates of the survivors, suggesting that many trees were adversely affected but not to the point of death.

There’s more after the jump. . . Continue reading