Man-made Warming the Main Cause of Glacier Retreat -Study

Posted by Eric Haun
Thursday, August 14, 2014
Photo Credit: O. Baranova

Man-made greenhouse gas emissions have become the dominant cause of melting in glaciers from the Alps to the Andes that is raising world sea levels, a study said on Thursday.

Human emissions accounted for an estimated 69 percent of loss of ice from glaciers from 1991-2010, overtaking natural climate variations that had been the main driver of a retreat since the mid-19th century, researchers wrote in the journal Science.

Until now, scientists have struggled to quantify the impact of human behaviour on glaciers because the frozen rivers of ice take decades, perhaps centuries, to respond to rising temperatures and shifts in snow and rainfall.

The study published on Thursday used historical observations of glaciers around the world, except in Antarctica, twinned with computer models to simulate all factors that could explain the retreat. It found that natural variations were not enough on their own, meaning man-made greenhouse gases played an increasing role.

"This is more evidence of human influence on the climate," Ben Marzeion, of the University of Innsbruck in Austria and lead author of the study, told Reuters.

The scientists estimated that human influences accounted for only about 25 percent of glaciers' total retreat since 1850 - meaning that natural swings in the climate, such as changes in the sun's output, have long been dominant.

Little Ice Age
Many glaciers grew during a period known as the Little Ice Age from 1350 to 1850, perhaps caused by a natural decline in the sun's output or sun-dimming volcanic eruptions.

Michael Zemp, head of the World Glacier Monitoring Service at the University of Zurich, said snowfall declined after around 1850. Rising temperatures from about the 1890s, when wider burning of coal meant more greenhouse gases, hastened the thaw.

"The big majority of glaciers have been retreating over the past century," he told Reuters. "We even have an accelerated retreat in recent decades." Glaciers have also varied widely - many Alpine glaciers advanced in the 1970s and 1980s.

Thursday's study estimated that water from melting glaciers has contributed a total of 13.3 cms (5 inches) from 1851-2010 to rising sea levels. Without human influences the rise would still have been 9.9 cms (4 inches).

Zemp said that greenhouse gases already in the atmosphere meant that glacier retreat and related sea level rise would continue for decades, even if emissions were to stop now.

Melting glaciers, especially in the Himalayas, also supply water vital to millions of people. A Chinese newspaper said that Tibet was warmer over the past 50 years than at any time in the past 2,000.

Pinning down a human influence on temperatures has been easier. A U.N. scientific panel said last year that it was at least 95 percent probable that mankind was the main cause of higher surface temperatures since 1950.

(By Alister Doyle, Environment Correspondent; Reporting by Alister Doyle; Editing by Ruth Pitchford)

Maritime Reporter February 2015 Digital Edition
FREE Maritime Reporter Subscription
Latest Maritime News    rss feeds

Environmental

First LNG-powered EcoLiner Launched

Europe’s greenest inland vessel debuts Damen group innovations   Damen Shipyards Group launched the first LNG-powered Damen EcoLiner inland shipping tanker

St. Lawrence Seaway Opening Date Pushed Back

Tthe opening date for the St. Lawrence Seaway 2015 navigation season has been delayed following review and consideration of factors and conditions affecting safe

Drop in Cocoa Bean Size Worries Ivorian Exporters

Dry weather in top cocoa grower Ivory Coast has caused a sharp drop in bean size and will delay the start of the April-to-September mid-crop by nearly two months,

News

Zamakona to Deliver Tuna Freezer Vessel

Zamakona Yards to deliver tuna freezer vessel Jai Alai to the Echebastar Group   This Saturday, March 7, Zamakona Shipyards in Santurce will deliver its construction number 737,

St. Lawrence Seaway Opening Date Pushed Back

Tthe opening date for the St. Lawrence Seaway 2015 navigation season has been delayed following review and consideration of factors and conditions affecting safe

Drop in Cocoa Bean Size Worries Ivorian Exporters

Dry weather in top cocoa grower Ivory Coast has caused a sharp drop in bean size and will delay the start of the April-to-September mid-crop by nearly two months,

Marine Science

Caterpillar to Stay in Peoria

After a multiyear study focused on modernizing its global headquarters, Caterpillar Inc. today reaffirmed it will remain in Peoria, Illinois, and revealed a

Rushton Gregory Inks Gemeco Marketing Deal

Rushton Gregory Communications announced today the latest addition to its industry-leading client roster, Gemeco Marine. Based in Lake City, South Carolina,

Holland America Line Heads NOAA's List of Weather Observations

Holland America Line topped the list in 2014 for the World’s Leading Weather Observing Cruise Ship Companies who submitted weather information to the National

Arctic Operations

Martian Ocean Held More Water than the Arctic

The National Aeronautics and Space Administration say there was once more water on the planet Mars than in the Arctic Ocean on Earth.   In a new study in the journal Science,

Arctic on Thin Ice

Arctic sea ice - the ice that freezes and floats on Arctic waters - is thinning at a steadier and faster rate than researchers previously thought, a new study finds.

Zeroing in on Zukunft

The U.S. Coast Guard Commandant addresses a packed Passenger Vessel Association meeting and outlines both the challenges and opportunities facing his organization.

Offshore Energy

New Floating Installation Concept for Offshore Wind

Conquest Offshore, together with deugro Denmark A/S, has developed an installation system for monopiles and transition pieces, supported by Temporary Works Design (TWD) and Barge Master.

Royal IHC Merges Four Units into IHC IQIP

Royal IHC (IHC) has integrated four of its business units – IHC Hydrohammer, IHC Handling Systems, IHC Sea Steel and IHC Fundex Equipment – into one new organization,

CTruk OWSV Enhanced with Volvo IPS

Since the launch of its first-of-class CTruk MPC22 late last year, the East Anglia-based workboat designer and builder informs it has incorporated performance feedback

 
 
Maritime Security Maritime Standards Naval Architecture Navigation Offshore Oil Pipelines Pod Propulsion Salvage Ship Electronics Sonar
rss | archive | history | articles | privacy | terms and conditions | contributors | top maritime news | about us | copyright | maritime magazines
maritime security news | shipbuilding news | maritime industry | shipping news | maritime reporting | workboats news | ship design | maritime business

Time taken: 0.1525 sec (7 req/sec)