Posts Tagged "Climate Change"

Climate Change Increases Flood Risk in Peru

Posted by on Dec 28, 2016 in All Posts, Featured Posts, Images, News, Policy and Economics, Science | 0 comments

Climate Change Increases Flood Risk in Peru

Spread the News:ShareThe rising danger of glacial lake flooding in a warmer climate has important implications for humans and animal populations in Peru’s Cordillera Blanca. A recent study in CATENA by Adam Emmer et al. examined a large swath of nearly 900 high altitude Peruvian lakes in the mountainous Cordillera Blanca region, studying their susceptibility to outburst floods in light of modern climate change. An outburst flood occurs when the dam containing glacial meltwater, usually comprised of either glacial ice or a terminal moraine (glacial debris lying at the edge of the glacier), fails. Glaciologist Mauri Pelto commented in the American Geophysical newsletter that the moraine dams are “just comprised of gravel, sand and clay dumped by the glacier” and “high water levels caused by upstream floods, avalanches or landslides can cause failure,” leading to major damage of the landscape. The team’s research elucidated that the incidence of glacial lake outburst flooding (GLOF) is increasing and the general distribution of alpine lakes is shifting upward in the region as temperatures warm.  Knowing a lake’s size, configuration and type allows local water management in the Cordillera Blanca to be improved, according to Emmer et al. By mapping lakes with the classification of either moraine-dammed or bedrock-dammed, the team’s analysis can help local hydrological experts improve water management techniques for the changing distribution of alpine water. It also contributes to the scientific community’s overall understanding of ongoing environmental change. By studying the Cordillera Blanca region’s alpine lakes through a combination of remote sensing (high resolution aerial imagery and measurements) and field observations, Emmer’s team categorized 882 lakes by their size and altitude, ultimately referencing their findings with historical data to observe water redistribution over the last 60 years. Emmer et al. established that glacial lakes had expanded in size and number at higher elevations and disappeared at lower elevations since the 1951 study by Juan Concha in the same region. This finding confirms that environmental change and glacier retreat are strongly correlated in the high alpine. Results from the analyses showed that from 1948 to 2013, lakes that remained in already deglaciated areas tended to be resilient and generally maintained water levels throughout the 65-year examination. Moraine-dammed lakes in particular resisted disappearing despite glacial retreat, suggesting that bodies of water dammed by materials other than ice were more adaptable to recently warmer temperatures.  The team also noticed that despite the recent resiliency of moraine dammed lakes, glacial lake outburst flooding was caused predominantly by these dams in the early portion of the Cordillera Blanca’s glacial retreat, in the 1940s and 1950s. Flooding in more recent years has occurred in bedrock-dammed lakes. Although glacial lakes were recorded to have shifted from 4250-4600m in the late 1940s to predominantly above 4600m today, no statistically significant trend was established relating outburst flooding to any particular elevation. In order to reduce the risk of flood damage in local communities, Emmer et al. suggested continuous monitoring of young, developing proglacial lakes, using extensive flood modeling and outburst susceptibility assessments to account for future changes in the glacier. Understanding that the melting of glaciers is accelerating in a warming world, the need for more intensive local efforts in response to the threat of flooding is apparent.   The Peruvian government has responded to high lake levels in the mountains of the Cordillera Blanca by “building tunnels and concrete pipes through the [weakest] moraines to allow lake drainage to safe levels,” according to Pelto. The government then rebuilds the moraines over the drainage system to strengthen it. By incorporating the monitoring techniques suggested by Adam Emmer, the government has the...

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Glacial Retreat Causes A Yukon River to Disappear

Posted by on Dec 14, 2016 in All Posts, Communities, Featured Posts, News, Science | 0 comments

Glacial Retreat Causes A Yukon River to Disappear

Spread the News:ShareMuch to the alarm of Canadians, the glacier-fed Slims River has disappeared following extensive glacial melting associated with anthropogenic climate change. Views of the Slims Valley, where the river once flowed, have been replaced by a dry plain, marked only by the sinuous bevels left behind by the river in the soil. These changes have major implications on local ecosystems and will inevitably result in lower water levels in downstream glacial lakes. For example, for many years, the Yukon’s Kluane Lake has been fed by the continuous flow of the Slims River. Water in the Slims River had been transported from Kaskawulsh Glacier, feeding the Kluane Lake and flowing into the Bering Sea. The Kaskawulsh Glacier is a large temperate valley glacier that lies in the St. Elias Mountains. It measures more than four miles across at its widest, where it meets the Slims and Kaskawulsh Rivers. With the recent melting of the glacier, water has been diverted in the direction of the Kaskawulsh River, which drains nearly 500 kilometers away in the Gulf of Alaska. Jeff Bond of the Yukon Geological Survey stated to Paul Tukker of CBC News, “Folks have noticed this spring that the [river has] essentially dried up.” This loss of streamflow is the first regional occurrence in the last 350 years, according to the Yukon Geological Survey. Some of the warmest temperatures on record in 2015 and 2016 have had major implications on glacial health in the region, with ice loss reported throughout the surrounding Saint Elias Mountains, as reported by the National Oceanic and Atmospheric Administration (NOAA). The rangers in the Kluane National Park noted that the Kaskawulsh Glacier has retreated nearly a half mile to the point where its melt water is now traveling in a completely different direction. In this case, the diversion of glacial meltwater is so substantial that no water is flowing in the direction of the Slims Valley and the downstream Bering Sea. Despite the Slims normally flowing approximately 19 kilometers from the edge of the glacier to Kluane Lake through the Slims Valley, changes to the Kaskawulsh’s spatial distribution have caused meltwater to flow not westward but to the east, flowing into the Pacific Ocean. The change in water patterns has major implications for ecosystems in regions experiencing new levels of flow (both in the dryer and the now wetter areas). For example, in the absence of perennial water, the Slims Valley is more prone to dust storms, at least until new vegetation stabilizes the floodplain. Retired Utah Geological Survey geomorphologist Will Stokes told GlacierHub, “The valley may undergo a major ecological evolution over the next few decades, characterized by new flora and fauna.” Although this may seem like a minor adjustment, Stokes explained, “These changes can drastically alter the local food chain, and if lake levels end up lowering dramatically, there may be a major negative impact on local hunting and fishing.” Jeff Bond further speculated to CBC News that the melt-water system which fed the Slims Valley may have only been a temporary outflow from the Kaskawulsh Glacier, representing a “300-year blip” on a much longer geological timescale in which large glaciers evolve. A study by Harold Borns in the American Journal of Science supports the notion that water began flowing northward around the year 1700, when climatological events caused the glacier to advance, ultimately diverting a large portion of snowmelt towards the Slims Valley and creating the Kluane Lake. This relationship illustrates the impact that regional climate has had on glacial events, with recent warming reversing the changes that occurred in a...

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Toxic Algal Blooms: Expert Adaptors to Climate Change

Posted by on Nov 3, 2016 in All Posts, Featured Posts, Science | 0 comments

Toxic Algal Blooms: Expert Adaptors to Climate Change

Spread the News:ShareMost people think of algae as the bothersome green stuff that grows on the tops of ponds and needs to be removed from the inside of fish tanks, but algae also provides clues about the environment. The response of Harmful Algal Blooms (HABs) to climate change, for example, provides evidence that some algae are extremely efficient environmental adaptors. HABs are formed when colonies of algae living in fresh or saltwater grow out of control and begin producing toxic effects that can threaten the health and lives of animals and humans. According to NOAA, they have occurred in every coastal state in the United States and are increasing in frequency due to rising temperatures associated with climate change. As a result, HAB responses to climate change, including changes in pH and CO2, have been increasingly studied. These responses include the expansion of the blooms into larger areas and an increased release of toxic poisons with warming temperatures. In a recently published paper, Mardones et al examine a special type of algal bloom found to be an expert adaptor to climate change. This strain of algal blooms called Alexandrium catenella occurs in highly variable fjord systems in southern Chile.  These Chilean fjords have had to respond to fluctuations in CO2 and pH. They experience huge freshwater inputs from Patagonian ice fields and heavy precipitation events. When dissolved in water, CO2 forms carbonic acid, which has a low pH. Therefore, levels of CO2 and pH are inversely correlated. As CO2 increases due to climate change, algal blooms in the fjords produce more Paralytic Shellfish Toxin (PST). This toxin could have long-term effects on the fish population and therefore the entire food web and ecosystem in the fjord. In an article by Pedro Costa, he describes how these neurotoxins can have a lasting impact: poisoned fish can be consumed by seals and humans, causing health issues or even death. As we expect CO2 to continue to rise, it is very likely harmful algal blooms like the ones in Chile will produce more PST, leading to more fish kills, disturbed ecosystems in the fjords, and possible human health issues. During their research, Mardones et al explored six levels of CO2/pH and two light conditions to examine how the algal blooms react. The scientists identified key differences in the waters in the fjord closest to the melting ice fields and the waters in the fjord further offshore. The near-shore water in the fjord experiences the largest impact of the freshwater inputs from the ice fields. The freshwater means that the upper layers of the water are much less salty compared to lower layers. This creates an intense halocline (stronger layers of differences in salinity) in the water column.  Strong winds in the region mix the layers, which produce highly fluctuating differences in carbonate chemistry. As Patagonian glaciers continue to melt, even more freshwater will be introduced into the fjords, which will continue to change the conditions of the water.   On the other hand, the more stable offshore waters have CO2 equilibrium with the atmosphere. The main environmental driver offshore is human-caused ocean acidification. As CO2 emissions increase in the atmosphere, it dissolves in oceans and lowers the pH of the water. For most species, this causes huge problems, but certain types of algal blooms are able to adapt to these conditions. Previous studies done by Tatter et al. show that a type of the same algal bloom from Southern California have previously changed their physiological responses due to changing pCO2/pH. Under higher CO2 conditions, production of Paralytic Shellfish Toxin increased. In 2015, there...

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Patagonian Ice Holds the Key to Unlocking the Past

Posted by on Nov 2, 2016 in All Posts, Communities, Featured Posts, Images, Science, Tourism | 0 comments

Patagonian Ice Holds the Key to Unlocking the Past

Spread the News:ShareA research team recently conducted a study in the Northern Patagonia Ice Field (NPI) to uncover some of the mystery behind Earth’s ancient climate. Along the way, the team made important observations about the current state of glacial ice thinning and climate change. Through their investigation of ancient paleoclimates (climates prevalent in the geological past), the scientists were able to identify time periods where major glacial growth and decline occurred in the Patagonian Ice Field, contributing important information to our understanding of our planet’s climate following the last ice age. Developing a strong comprehension of glacial advance and retreat over the last 10,000 years in places like the Patagonian Ice Field provides the scientific community with tools to augment our understanding of the past, as the planet’s climate is intrinsically related to its ecology at any given point in our recent geological history. Patagonia hosts a wide variety of largely untouched landscapes, possessing a range of environments from mountains and deserts to glaciers and grasslands. In addition to its mountainous beauty, the Northern Patagonia Icefield is special in that it is the most glaciated terrain on the planet within its latitude of 46.5 to 47.5 degrees south. The region where the ice field lies is a barren sector of South America spanning nearly 3 million square kilometers across southern Argentina and Chile. In the glaciated terrain, thick layers of ice and rock hold a wealth of information regarding global climates of the last 25,000 years, offering a glimpse of where we are headed given the recent anthropogenic (human-caused) acceleration of climate change. The study provided scientists with valuable climate data from the Late Pleistocene and Holocene time periods, which began approximately 125,000 years ago following the final episode of widespread global glaciation. The lead researchers of the study, David Nimick and Daniel McGrath, focused specifically on the the largest outlet glacier draining in the region, the Colonia Glacier on the eastern flank of the ice field. The team sought to constrain the ages of major glacial events by using a variety of dating techniques, including dendrochronology (tree-ring dating), radiocarbon dating, lichenometry (utilizing lichen growth to determine the age of exposed rock) as well as optically stimulated luminescence (dating the last time quartz sediments were exposed to sunlight). Employing such a wide variety of experimental techniques can be a valuable tool in improving the confidence of data and allowed the team to study a diversity of unique properties of the same glacial medium.   By examining properties of lichen and quartz grains (when they were last exposed to sunlight), the research team was able to  constrain the time at which specific rocks were uncovered from the ice sheets. The age at which the ice melted away to reveal these rocks corresponds to events of retreat (and subsequent advance) of glacial ice across the last few millennia. The determination of major glacial events using these techniques sheds light on the climatic events that not only influenced South American paleoclimate but also may affect present and future glacial retreat given the recent spike in atmospheric carbon dioxide levels. Results from dating analyses indicated that the most prominent increase in glaciated terrain occurred 13,200 years ago, 11,000 years ago and 4,960 years ago, with the last major advance defining the onset of Neoglaciation – the period of significant cooling during the Holocene or present day epoch. Analysis of a local ice-dammed lake revealed that glacial growth occurred 2,900 years ago and 810 years ago, with ice retreating during the intervening periods. This data points to the idea that in a general...

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Roundup: Pakistan’s Glaciers, Jobless Sherpas, Ancient Rivers

Posted by on Aug 15, 2016 in All Posts, Featured Posts, News, Roundup | 0 comments

Roundup: Pakistan’s Glaciers, Jobless Sherpas, Ancient Rivers

Spread the News:ShareThis Week’s Roundup: Pakistan has more glaciers than almost anywhere on Earth. But they are at risk. From The Washington Post: “For generations, the glacier clinging to Miragram Mountain, a peak that towers above the village, has served as a reservoir for locals and powered myriad streams throughout Pakistan’s scenic Chitral Valley. Now, though, the villagers say that their glacier — and their way of life — is in retreat…. With 7,253 known glaciers, including 543 in the Chitral Valley, there is more glacial ice in Pakistan than anywhere on Earth outside the polar regions, according to various studies. Those glaciers feed rivers that account for about 75 percent of the stored-water supply in the country of at least 180 million. But as in many other parts of the world, researchers say, Pakistan’s glaciers are receding, especially those at lower elevations, including here in the Hindu Kush mountain range in northern Khyber Pakhtunkhwa province. Among the causes cited by scientists: diminished snowfall, higher temperatures, heavier summer rainstorms and rampant deforestation.” Read the full story here.   Sherpas Denied Summit Certificates From The Himalayan Times: “The Department of Tourism, under the Ministry of Culture, Tourism and Civil Aviation, has refused to award high-altitude workers summit certificates, citing a clause of the Mountaineering Expedition Regulation that bars them from obtaining government certificates…. He said DoT couldn’t issue certificates to Sherpas as per the existing law, claiming that high-altitude workers are not considered a part of the expedition as per the Mountaineering Expedition Regulation that was framed in 2002. ‘The regulation considers only those who obtain climbing permit by paying royalty to the government as members of an expedition’ [Laxman Sharma, Director at DoT’s Mountaineering Section, told THT]. This is the first time in the country’s mountaineering history that Sherpas have failed to obtain government certificates despite successfully scaling mountains.” Read the full article here.   Ancient Rivers Beneath Greenland Glacier From Live Science: “A network of ancient rivers lies frozen in time beneath one of Greenland’s largest glaciers, new research reveals. The subglacial river network, which threads through much of Greenland’s landmass and looks, from above, like the tiny nerve fibers radiating from a brain cell, may have influenced the fast-moving Jakobshavn Isbrae glacier over the past few million years. ‘The channels seem to be instrumental in controlling the location and form of the Jakobshavn ice stream — and seem to show a clear influence on the onset of fast flow in this region,’ study co-author Michael Cooper, a doctoral candidate in geography at the University of Bristol in the United Kingdom, told Live Science. ‘Without the channels present underneath, the glacier may not exist in its current location or orientation.” Full story continued here. Spread the...

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