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少吃肉可降低氣候變遷帶來的經濟損失

Sun, 04/05/2009 - 12:53 — epadmin

資料來源: 新科學家 2009年2月10日作者: Jim Jiles http://www.newscientist.com/article/dn16573-eating-less-meat-could-cut-climate-costs.html?DCMP=OTC-rss&nsref=online-news

 
重點摘要 : 減量攝取牛肉漢堡和培根可節省對抗氣候變遷二十兆美元的成本。這戲劇性的結論來自一份加總現代多肉飲食所付出經濟代價的報告。
 
Stehfest以穩定二氧化碳含量在百萬分之450水準(那是一些科學家說，需要幫助防止危險的乾旱和海平面上升的安全水準)的花費，估算了牛肉和其他肉類食用量的降低，對經濟上產生的影響。如果飲食習慣不改變，Stehfest估計，排放量到2050年必須削減三分之二，可能約為四十兆美元的花費。  
 
但是，如果全球人口轉移到低肉飲食 (其定義每週食用70公克的牛肉和325公克的雞肉和雞蛋) ，約一千五百萬平方公里的農田將被釋放。生長在這片土地上的植被將吸取大量二氧化碳。 它也可被用來種植可取代化石燃料的生質能源作物。她計算出，由於牲畜數目的減少，溫室氣體排放量也下降了10 ％。加總起來，到2050年總影響將減少處理氣候變遷一半的費用。 

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減量攝取牛肉漢堡和培根可節省對抗氣候變遷二十兆美元的成本。這戲劇性的結論來自一份加總現代多肉飲食所付出經濟代價的報告。  

研究學者說，削減我們牛肉和豬肉的攝取量後，因閒置農田而欣欣向榮的植被，將導致生成一個巨大且新的碳匯。
 
該模型考量到為彌補失去的肉量，額外的農田被轉用來生產糧食，但因所需農地面積少於退牧之規模，因此有些會被閒置。而閒置農場原本每年所排放的百千萬噸強效溫室氣體甲烷，也將被省下。
 
荷蘭環境評估署埃爾克斯‧Stehfest和同事說，這些影響將減少如發電廠「潔淨煤」等昂貴省碳技術的需要，因而節省巨額資金。
 
脹氣的進食者
氣候變遷專家已警告了數年肉的高碳成本了。
 
牛肉是特別有害。乳牛腸氣和其腐敗糞便所排放的，乃是強效溫室氣體甲烷。此外，生產一公斤牛肉（2.2磅），農民也需餵養一頭牛15公斤穀物和30公斤的飼料。穀物需要化肥，而化肥則須密集能源才能生產。
 
Stehfest以穩定二氧化碳含量在百萬分之450水準(那是一些科學家說，需要幫助防止危險的乾旱和海平面上升的安全水準)的花費，估算了牛肉和其他肉類食用量的降低，對經濟上產生的影響。如果飲食習慣不改變，Stehfest估計，排放量到2050年必須削減三分之二，可能約為四十兆美元的花費。  
 
但是，如果全球人口轉移到低肉飲食 (其定義每週食用70公克的牛肉和325公克的雞肉和雞蛋) ，約一千五百萬平方公里的農田將被釋放。生長在這片土地上的植被將吸取大量二氧化碳。 它也可被用來種植可取代化石燃料的生質能源作物。
 
綠超市標籤
她計算出，由於牲畜數目的減少，溫室氣體排放量也下降了10 ％。加總起來，到2050年總影響將減少處理氣候變遷一半的費用。
 
Stehfest說，為了引導消費者，以單位碳排放為基準的肉食環境成本，也可納入食品採購價格。
                              
加拿大農業和農產食品部雷蒙德‧賈斯丁說，這費用聽起來沒錯。然而他補充說，以現在的農場來估算未來的農場經濟，或許是不公平的。
 
Original:
Eating less meat could cut climate costs
14:49 10 February 2009 by Jim Giles
 
Cutting back on beefburgers and bacon could wipe $20 trillion off the cost of fighting climate change. That's the dramatic conclusion of a study that totted up the economic costs of modern meat-heavy diets.
The researchers involved say that reducing our intake of beef and pork would lead to the creation of a huge new carbon sink, as vegetation would thrive on unused farmland.
The model takes into account farmland that is used to grow extra food to make up for the lost meat, but that requires less area, so some will be abandoned. Millions of tonnes of methane, a potent greenhouse gas, would also be saved every year due to reduced emissions from farms.
These impacts would lessen the need for expensive carbon-saving technologies, such as "clean coal" power plants, and so save huge sums, say Elke Stehfest of the Netherlands Environmental Assessment Agency and colleagues.
Flatulent feeders
Climate-change experts have warned of the high carbon cost of meat for several years.
Beef is particularly damaging. Methane, a potent greenhouse gas, is released from flatulent cows and by manure as it decays. Furthermore, to produce a kilogram of beef (2.2 pounds), farmers also have to feed a cow 15 kg of grain and 30 kg of forage. Grain requires fertiliser, which is energy intensive to produce.
Stehfest has now weighed the economic impact of beef and other meats against the cost of stabilising carbon dioxide levels at 450 parts per million – a level that some scientists say is needed to help prevent dangerous droughts and sea level rises.
If eating habits do not change, Stehfest estimates that emissions would have to be cut by two-thirds by 2050, which is likely to cost around $40 trillion.
If, however, the global population shifted to a low-meat diet – defined as 70 grams of beef and 325 grams of chicken and eggs per week – around 15 million square kilometres of farmland would be freed up. Vegetation growing on this land would mop up carbon dioxide. It could alternatively be used to grow bioenergy crops, which would displace fossil fuels.
Supermarket labels
Greenhouse gas emissions would also fall by 10% due to the drop in livestock numbers, she calculates. Together, these impacts would halve the costs of dealing with climate change by 2050.
To help consumers, the environmental cost of meat, in terms of carbon emissions per portion, could also be included in the purchase price, says Stehfest.
The costs sound about right, says Raymond Desjardins of Agriculture and Agri-Food Canada. However, it may be unfair to compare future farms to current ones, he adds.