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 August 2014 Digital Edition
FREE Maritime Reporter Subscription
Latest Maritime News    rss feeds

Environmental

Vessel Discharge Legislation Awaits Congressional Nod

The American Waterways Operators, a 350-member trade association representing the U.S. tugboat, towboat and barge industry, hailed the House introduction of

Dann Marine Repowers With Cummins Tier 3 Engines

Dann Marine Towing, LC., is a fifth generation family owned and operated tugboat company based in Chesapeake City, MD. The model-bow twin-screw tug Sea Coast was

Sulzer Shareholder has 5 pct Dresser-Rand Stake

Russian billionaire Viktor Vekselberg's Swiss investment firm Renova Group said on Friday it had a 4.99 percent stake in U.S.-based Dresser-Rand, which might become the object of a takeover battle.

News

Vessel Discharge Legislation Awaits Congressional Nod

The American Waterways Operators, a 350-member trade association representing the U.S. tugboat, towboat and barge industry, hailed the House introduction of

Seagull Maritime Response on Safety, Security

Key areas of concern for seafarer safety and security in both marine and offshore operations have triggered the release of six new and one supplementary titles

Antwerp Port Seeks Inputs on Setting-up LNG bunkering

By the beginning of 2016 the port of Antwerp will have an LNG bunkering and filling station for barges. The procedure for construction of the station is currently under way.

Marine Science

Seagull Maritime Response on Safety, Security

Key areas of concern for seafarer safety and security in both marine and offshore operations have triggered the release of six new and one supplementary titles

AN/SPY-1 SSSA Completes Critical Design Review

The Critical Design Review (CDR) stage for AN/SPY-1 radar Solid-State Switch Assembly (SSSA)'s high voltage modulator completed Aug. 26, confirming that the

Caterpillar to Participate in Citi 2014 Industrials Conference

Caterpillar Inc. Vice President with responsibility for Strategic Services Mike DeWalt and Director of Investor Relations Rich Moore will speak at the Citi 2014 Industrials Conference on Tuesday,

Arctic Operations

Exxon: U.S. to Allow Wind Down Ops in Russian Arctic

U.S. oil major Exxon Mobil said on Friday the U.S. Treasury Department granted it a license to wind down operations on a drilling well in the Kara Sea in the Russian Arctic.

Russia: Exxon Still Drilling in its Arctic

ExxonMobil is still drilling in the Russian Arctic, a Russian minister said on Friday, in move that if confirmed will anger Washington after the U.S. administration

Exxon, Rosneft May Halt Arctic Operations

Russia's natural resources minister said on Friday that it was highly likely that U.S. oil major Exxon Mobil Corp and its Russian counterpart Rosneft had halted

Offshore Energy

Exxon: U.S. to Allow Wind Down Ops in Russian Arctic

U.S. oil major Exxon Mobil said on Friday the U.S. Treasury Department granted it a license to wind down operations on a drilling well in the Kara Sea in the Russian Arctic.

Russia: Exxon Still Drilling in its Arctic

ExxonMobil is still drilling in the Russian Arctic, a Russian minister said on Friday, in move that if confirmed will anger Washington after the U.S. administration

FPSO Petrojarl Knarr Delivered to Norway

Three tugs of Fairmount Marine have towed the brand new FPSO Petrojarl Knarr from South Korea to Norway in just 61 days. Petrojarl Knarr, one of world’s largest

 
 
Maritime Careers / Shipboard Positions Maritime Contracts Maritime Security Maritime Standards Navigation Offshore Oil Pipelines Pod Propulsion Shipbuilding / Vessel Construction Winch
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: 0.1210 sec (8 req/sec)