到2050年，世界人口將新增25億（相當於中國和印度當下人口的總和），我們怎樣才能養活這麼多人？聯合國估計，我們必須將目前的食物產量翻一番才能滿足需求；各國政府也宣稱，應該采用新技術並避免浪費。但無論如何節約，世界長期飢餓人口已經達到了10億；未開墾土地寥寥無幾；氣候變化加大了很多地區農業生產的難度；海洋魚類過度捕撈；世界許多地區水資源短缺愈演愈烈。
五十年前，當世界人口只有如今的大約一半時，人類曾希望用所謂的“綠色革命”阻止迫在眉睫的糧食危機。雜交種子和化肥使用量的猛增取得了一些效果，但人類也付出了沉重的生態代價。與父輩相比，我們的糧食產量將近翻了一番，但對地表和地下水的消耗卻增長了兩倍。
食品、農業和水利等領域的技術專家必須找到新的方法，讓從前很難或者根本不可能發展農業的地方成為我們的糧倉。或許我們需要重新思考應該如何使用土地和水資源。全新一代的尖端農民、奇特食品及精彩創意也應運而生。
藻類
怎樣才能在大量減少耕地使用的前提下生產出更多可以養活人類的食物？要做到這點其實十分簡單——只要我們將精力轉向商業化的藻類養殖。藻類是一種單細胞生物，結構並不復雜，在海洋裡、污水中以及其他糧食作物無法存活的環境中都能快速生長繁殖。多家大型航空公司和海運集團都在研究使用海藻油的可能性，精明的清潔能源投資者更是將錢源源不斷地投入這項尚處在發展初期的技術之中。
藻類養殖的回報極高：據科學家估算，在最理想條件下，商業藻類養殖每英畝（約合4050平方米）可產出5000到10000加侖（大約22730到45460公升）海藻油；而相比之下，用玉米等糧食作物生產生物乙醇每英畝產量只有350加侖（約合1590公升）。另外，藻類還可以用作動物飼料和肥料。用海藻油替代美國市面上全部生物乙醇需要占用大約二百英畝（8000多平方公裡）沙漠，但正如亞利桑那州立大學教授馬克·愛德華茲所說，這也意味著將騰出4000萬英畝（約合162000平方千米）的農田和每年幾百萬加侖的灌溉水用來為人類生產糧食。
雖然處在食物鏈的底部，但海帶等藻類一直以來就是日本和中國餐桌上的佳肴，並且已經用作肥料、土壤改良劑和動物飼料。愛德華茲說：“藻類大的如海帶、巨藻，小的只有顯微鏡才能觀測到；它們能固定大氣中的二氧化碳並提供脂肪、油類和糖分。自然界無論是小蝦還是藍鯨都以它們為食。藻類是所有生命的基礎，也是人類未來的依靠。”
人造肉
這種東西看起來像肉，摸起來像肉，也的確是肉，只不過不是從喘氣兒的活體動物身上取下來的。相反，人造肉是利用干細胞在大型容器中“人工培養”出來的。
科學家認為，尋找肉類的替代品十分重要。因為在中國等快速發展的新興經濟體，人們的飲食習慣正向西方靠攏，這使政府和農民不得不砍伐森林以開發新的農場。目前有將近四分之一的可耕地用於養牛，另有四分之一用於種植動物飼料。在美國，牲畜飼料在全部谷物生產中所占的比重已經達到將近七成。
目前，大部分人造肉的研究都是在歐洲進行的，其中荷蘭和英國的科學家已經成功地在實驗室中利用干細胞培養出可以食用的組織結構。不過，雖然首個用人造肉制成的漢堡明年便有望問世，但它的味道可能會令人大失所望。肉類的顏色和口味分別來自血液和脂肪。雖然研究人員已經找出了能做出血液和脂肪的干細胞，但真正制成人造血液和脂肪還是一項漫長、復雜而昂貴的工作。
即便如此，研究證明人造肉在環境方面的益處是普通肉類無法比擬的，其生產過程中所需的水、能量和土地都更少。另外，在大規模農場飼養以及生長激素和抗生素的使用已經飽受質疑之時，人造肉卻幾乎不涉及任何道德爭議。
新型糧食作物
很少有人聽說過黎志康這個名字，但這位中國植物育種專家很可能將作為本世紀最重要的人物之一而永載史冊。在中國農業科學院和菲律賓國際水稻研究所工作12年之後，黎志康和他的科研團隊去年開發出了“綠色超級稻”。經驗證，這一系列稻種不僅產量更高，而且更耐旱、耐澇、耐鹽，還更能抗蟲害、抗病。
黎志康沒有使用轉基因技術，而是與來自16個國家的上百名研究院和農民合作，完全采用傳統育種技術將250多個稻種雜交選優。
這種能大幅度增加亞洲地區糧食產量、多養活1億人的綠色超級稻幾年之內即將正式推向市場。但對於其他作物來說，更好的植物育種——無論是否使用轉基因技術——也將是提高產量的關鍵。
然而在過去的20年中，大部分研究經費都用在了轉基因技術上。農用化學產業當初承諾，經他們改造的糧食作物不僅富含維生素、酵素或者健康脂肪酸，並且有很好的耐旱性，能減少碳排放。雖然我們有望看到能制造人類疫苗的香蕉、成熟期更短的魚和具有抗病性的牛，但“養活世界”的承諾仍遠未實現。
去年，全球轉基因作物種植面積超過3.5億英畝（約合140多萬平方公裡）——占全球耕地面積約10%，是德國、法國、英國國土面積的總和；但玉米、油菜及大豆占據了其中大部分，而這三種作物的產出大多用作動物飼料。
沙漠綠化
世界上有很多地區受干旱之苦，唯一鄰近的水源就是海洋。我們能不能開發一種技術，讓智利、加利福尼亞、秘魯和中東這樣的沿海沙漠利用海水實現綠化呢？
英國發明家查理·佩頓就有這樣一個設想：用廣闊的“海水溫室”種糧發電。他的計劃很簡單：在自然界的水循環中，海水經陽光加熱後蒸發，冷卻後形成雲，之後再以雨的形式回到地表。佩頓的設計采取了類似的結構。在這裡，炙熱的沙漠空氣在進入溫室後首先冷卻，再經海水加濕。潮濕的空氣在滋潤溫室中的農作物之後，將穿過一個蒸發裝置。當遇到一組裝有冷海水的冷卻管時，空氣中的水汽凝結成淡水，由工作人員統一收集。使用這種方法生產的淡水是溫室作物需水量的五倍，因此可以將一部分溫室中產生的淡水用於當地其他作物的灌溉。
海水溫室已經被證明行之有效，而且今年就會有一個由挪威政府支持的大型試點項目在約旦亞喀巴附近上馬。“撒哈拉森林計劃”將綜合利用不同的技術種植糧食和生物能源作物，將於2015年正式開始運行。
除此之外，還有許多新技術正在開發當中，它們將使人類得以在極端環境中種植糧食。或許其中最簡單卻最具雄心的項目就是籌劃已久的“非洲綠色長城”計劃了。這片長條狀的森林寬15公裡，長7775公裡，自西非的塞內加爾一直延伸到東非的吉布提。參與該計劃的非洲11國表示，“綠色長城”將有助於阻止撒哈拉沙漠向南擴展，減緩土壤退化，降低風速，促進雨水下滲，並創造出適宜種植水果、蔬菜和其他作物的小氣候。
昆蟲
在歐洲或是美國大多數餐廳的菜單上，像蝗蟲、蚱蜢、蜘蛛、黃蜂、蠕蟲、螞蟻和甲殼蟲這樣的東西是難得一見的；但在非洲、拉丁美洲和亞洲，人們食用的昆蟲多達1400種。隨著食品價格的上漲和世界範圍內土地供應緊張，英國等地建立食用昆蟲養殖場的日子也不遠了。
養殖昆蟲的優點不僅在於昆蟲是一種高蛋白、低脂肪、低膽固醇、高鈣高鐵的食物，還因為昆蟲養殖場占地很小。從環境角度看，傳統養殖場同樣不能和它相提並論。昆蟲將植物轉化為可食用肉質的速度比發育周期最短的家畜還要快；它們釋放的溫室氣體更少；無論喂它們紙張、水藻還是工業廢料，它們都能茁壯成長。
一直積極尋求大範圍推廣食用昆蟲養殖的聯合國和歐盟都十分推崇這種“微型家畜”的種種優點。荷蘭政府正在研究如何建立昆蟲養殖場。但出於對西方人神經質的照顧，他們要求研究人員看看能否單獨提取昆蟲蛋白。
與此同時，歐盟向其成員國提供300萬歐元資金推廣昆蟲在餐飲中的使用，並要求食品標准監管機構研究昆蟲作為膳食補充的可能性。
約翰•維達
By 2050 there will be 2.5 billion more people on earth. How can they be fed? Science’s answer, writes John Vidal, is a diet of algae, insects and meat grown in laboratories.
How can we feed the 2.5 billion more people – an extra China and India – likely to be alive in 2050? The United Nations says we will have to nearly double our food production and governments say we should adopt new technologies and avoid waste. But however you cut it: there are already one billion chronically hungry people; there’s little more virgin land to open up; climate change will only make farming harder to grow food in most places; the oceans are overfished; and much of the world faces growing water shortages.
Fifty years ago, when the world’s population was around half what it is now, the answer to looming famines was “the green revolution” – a massive increase in the use of hybrid seeds and chemical fertilisers. It worked, but at a great ecological price. We grow nearly twice as much food as we did just a generation ago, but we use three times as much water from rivers and underground supplies.
Food, farm and water technologists will have to find new ways to grow more crops in places that until now were hard or impossible to farm. It may need a total rethink over how we use land and water. So enter a new generation of radical farmers, novel foods and bright ideas.
Algae
How do you free up huge amounts of farmland to grow more food for humans? Easy – switch to commercial algae farms. Algae are simple, single-cell organisms that can grow very rapidly at sea, in polluted water and in places that would normally kill food crops. Major airlines and shipping companies are now investigating a switch to algae oil, and smart clean-tech money is pouring in to the nascent technology.
The prize is huge: scientists say that under optimum conditions, commercial algae farms can produce 5,000 to 10,000 gallons [roughly 22,730 to 45,460 litres] of oil per acre [nearly 4,050 square metres], compared to just 350 gallons [about 1,590 litres] of ethanol biofuel per acre grown with crops such as maize. In addition, algae could feed millions of animals and act as a fertiliser. Replacing all US ethanol (biofuel) production with algae oil would need around two million acres [just over 8,000 square kilometres] of desert, but, says Arizona State university professor Mark Edwards, it would potentially allow 40 million acres [about 162,000 square kilometres] of cropland to be planted with human food, and save billions of gallons of irrigation water a year.
Algae are at the bottom of the food chain but they are already eaten widely in Japan and China in the form of seaweeds, and are used as fertilisers, soil conditioners and animal feed. “They range from giant seaweeds and kelps to microscopic slimes; they are capable of fixing CO2 in the atmosphere and providing fats, oils and sugars,” says Edwards. “They are eaten by everything from the tiniest shrimp to the great blue whales. They are the base of all life and must be the future.”
Artificial meat
It looks like meat, feels like meat and it is meat, although it’s never been near a living, breathing animal. Instead, artificial or “cultured” meat is grown from stem cells in giant vats.
Scientists say the hunt for meat substitutes is critical because western eating habits are now spreading to China and other rapidly emerging economies, putting intense pressure on governments and farmers to fell more forests and open up new farmland. Cattle now occupy nearly one quarter of all cultivable land, and growing crops for animal feed takes up another 25%. In the United States, nearly 70% of the grain and cereals grown are now fed to farmed animals.
Much of the research into artificial meat is being done in Europe, with scientists in Holland and Britain developing edible tissue grown from stem cells in laboratories. But while the first artificial hamburger could be developed next year, it might taste of nothing at all. Meat needs blood and fat to give it colour and taste, and while stem cells for blood and fat have been identified, this is slow, complex and expensive work.
Nevertheless, studies show that artificial meat wins hands down in the environmental stakes, using far less water, energy and land. In addition, few ethical objections have been raised, largely because mass production of animals in factory farms and use of growth hormones and antibiotics is already considered questionable.
New crops
Few people have heard of Zhikang Li, but history may judge the Chinese plant breeder to be one of the most important people of the century. Last year, after 12 years’ work with the Chinese Academy of Agricultural Sciences (CAAS) and the International Rice Research Institute (IRRI) in the Philippines, he and his team developed “green super rice”, a series of rice varieties which produce more grain but which have proved more resistant to droughts, floods, salty water, insects and disease.
Zhikang Li achieved this without genetic modification (GM) technology, working instead with hundreds of researchers and farmers in 16 countries and using only conventional plant breeding techniques to cross-breed more than 250 rice varieties.
Green super rice, which could increase yields in Asia enough to feed an extra 100 million people, will be rolled out in the coming years. But better plant breeding – with or without GM – will be key to increasing the yields of all other crops.
However, most research money has gone into GM in the past 20 years. Here, the global agrichemical industry has promised new crops enriched with extra vitamins, enzymes or healthy fatty acids, as well as drought-tolerant corn and crops that can save carbon emissions. But while it looks ahead to bananas that produce human vaccines, fish that mature more quickly and cows that are resistant to disease, its promise to feed the world has been patchy in terms of results.
Last year more than 350 million acres (over 1.4 million square kilometres) – about 10% of global cultivated area, or the size of Germany, France and the United Kingdom together – were planted with GM crops; but this mainly covered only three big foods – maize, oilseed rape and soya – most of which went to animal feed.
Desert greening
Much of the world is arid, with its only nearby water being the sea. So could a technology be found to green coastal deserts in places such as Chile, California, Peru and the Middle East using salt water?
Charlie Paton, a British inventor, has a vision of vast “seawater greenhouses” to grow food and generate power. The idea is simple: in the natural water cycle, seawater is heated by the sun, evaporates, cools to form clouds, and returns to earth as refreshing rain. It is more or less the same in Paton’s structures. Here, hot desert air going into a greenhouse is first cooled and then humidified by seawater. This humid air nourishes crops growing inside and then passes through an evaporator. When it meets a series of tubes containing cool seawater, freshwater condenses and is then collected. And because the greenhouses produce more than five times the freshwater needed to water the plants, some of it can be released into the local environment to grow other plants.
Seawater greenhouses have been shown to work and this year a large-scale pilot project backed by the Norwegian government will be built near Aqaba in Jordan. The Sahara Forest Project will combine different technologies to grow food and biofuel crops and be up and running by 2015.
But this is just one of many technologies being developed to enable food to be grown in unlikely places. One of the simplest, but most ambitious, plans may be the long-mooted Great Green Wall of Africa. This linear forest would be 15 kilometres wide and 7,775 kilometres long, and stretch from Senegal in the west to Djibouti in east Africa. It would, say the 11 countries through which it would pass, help to stop the southward spread of the Sahara, slow soil erosion and wind speeds, help rain water filter into the ground and create micro-climates to allow fruit, vegetables and other crops to be grown.
Insects
Locusts, grasshoppers, spiders, wasps, worms, ants and beetles are not on most European or US menus but at least 1,400 species are eaten across Africa, Latin America and Asia. Now, with rising food prices and worldwide land shortages, it could be just a matter of time before insect farms set up in places such as Britain.
Not only are many bugs rich in protein, low in fat and cholesterol and high in calcium and iron, but insect farms need little space. Environmentally, they beat conventional farms, too. The creatures are far better at converting plant biomass into edible meat than even our fastest growing livestock; they emit fewer greenhouse gases; and they can thrive on paper, algae and the industrial wastes that would normally be thrown away.
The advantages of “micro-livestock” farming are great, say the United Nations and European Union, both of which are keen to see if insect rearing could be greatly expanded. The Dutch government is studying how to set up insect farms. But aware of western squeamishness, they have asked researchers to see if they can just extract the protein that many bugs contain.
Meanwhile, the EU is offering its member-states three million euros [more than US$3.9 million] to promote the use of insects in cooking, and has asked food-standards watchdogs to investigate their potential to supplement diets.
http://www.guardian.co.uk/
Fifty years ago, when the world’s population was around half what it is now, the answer to looming famines was “the green revolution” – a massive increase in the use of hybrid seeds and chemical fertilisers. It worked, but at a great ecological price. We grow nearly twice as much food as we did just a generation ago, but we use three times as much water from rivers and underground supplies.
Food, farm and water technologists will have to find new ways to grow more crops in places that until now were hard or impossible to farm. It may need a total rethink over how we use land and water. So enter a new generation of radical farmers, novel foods and bright ideas.
Algae
How do you free up huge amounts of farmland to grow more food for humans? Easy – switch to commercial algae farms. Algae are simple, single-cell organisms that can grow very rapidly at sea, in polluted water and in places that would normally kill food crops. Major airlines and shipping companies are now investigating a switch to algae oil, and smart clean-tech money is pouring in to the nascent technology.
The prize is huge: scientists say that under optimum conditions, commercial algae farms can produce 5,000 to 10,000 gallons [roughly 22,730 to 45,460 litres] of oil per acre [nearly 4,050 square metres], compared to just 350 gallons [about 1,590 litres] of ethanol biofuel per acre grown with crops such as maize. In addition, algae could feed millions of animals and act as a fertiliser. Replacing all US ethanol (biofuel) production with algae oil would need around two million acres [just over 8,000 square kilometres] of desert, but, says Arizona State university professor Mark Edwards, it would potentially allow 40 million acres [about 162,000 square kilometres] of cropland to be planted with human food, and save billions of gallons of irrigation water a year.
Algae are at the bottom of the food chain but they are already eaten widely in Japan and China in the form of seaweeds, and are used as fertilisers, soil conditioners and animal feed. “They range from giant seaweeds and kelps to microscopic slimes; they are capable of fixing CO2 in the atmosphere and providing fats, oils and sugars,” says Edwards. “They are eaten by everything from the tiniest shrimp to the great blue whales. They are the base of all life and must be the future.”
Artificial meat
It looks like meat, feels like meat and it is meat, although it’s never been near a living, breathing animal. Instead, artificial or “cultured” meat is grown from stem cells in giant vats.
Scientists say the hunt for meat substitutes is critical because western eating habits are now spreading to China and other rapidly emerging economies, putting intense pressure on governments and farmers to fell more forests and open up new farmland. Cattle now occupy nearly one quarter of all cultivable land, and growing crops for animal feed takes up another 25%. In the United States, nearly 70% of the grain and cereals grown are now fed to farmed animals.
Much of the research into artificial meat is being done in Europe, with scientists in Holland and Britain developing edible tissue grown from stem cells in laboratories. But while the first artificial hamburger could be developed next year, it might taste of nothing at all. Meat needs blood and fat to give it colour and taste, and while stem cells for blood and fat have been identified, this is slow, complex and expensive work.
Nevertheless, studies show that artificial meat wins hands down in the environmental stakes, using far less water, energy and land. In addition, few ethical objections have been raised, largely because mass production of animals in factory farms and use of growth hormones and antibiotics is already considered questionable.
New crops
Few people have heard of Zhikang Li, but history may judge the Chinese plant breeder to be one of the most important people of the century. Last year, after 12 years’ work with the Chinese Academy of Agricultural Sciences (CAAS) and the International Rice Research Institute (IRRI) in the Philippines, he and his team developed “green super rice”, a series of rice varieties which produce more grain but which have proved more resistant to droughts, floods, salty water, insects and disease.
Zhikang Li achieved this without genetic modification (GM) technology, working instead with hundreds of researchers and farmers in 16 countries and using only conventional plant breeding techniques to cross-breed more than 250 rice varieties.
Green super rice, which could increase yields in Asia enough to feed an extra 100 million people, will be rolled out in the coming years. But better plant breeding – with or without GM – will be key to increasing the yields of all other crops.
However, most research money has gone into GM in the past 20 years. Here, the global agrichemical industry has promised new crops enriched with extra vitamins, enzymes or healthy fatty acids, as well as drought-tolerant corn and crops that can save carbon emissions. But while it looks ahead to bananas that produce human vaccines, fish that mature more quickly and cows that are resistant to disease, its promise to feed the world has been patchy in terms of results.
Last year more than 350 million acres (over 1.4 million square kilometres) – about 10% of global cultivated area, or the size of Germany, France and the United Kingdom together – were planted with GM crops; but this mainly covered only three big foods – maize, oilseed rape and soya – most of which went to animal feed.
Desert greening
Much of the world is arid, with its only nearby water being the sea. So could a technology be found to green coastal deserts in places such as Chile, California, Peru and the Middle East using salt water?
Charlie Paton, a British inventor, has a vision of vast “seawater greenhouses” to grow food and generate power. The idea is simple: in the natural water cycle, seawater is heated by the sun, evaporates, cools to form clouds, and returns to earth as refreshing rain. It is more or less the same in Paton’s structures. Here, hot desert air going into a greenhouse is first cooled and then humidified by seawater. This humid air nourishes crops growing inside and then passes through an evaporator. When it meets a series of tubes containing cool seawater, freshwater condenses and is then collected. And because the greenhouses produce more than five times the freshwater needed to water the plants, some of it can be released into the local environment to grow other plants.
Seawater greenhouses have been shown to work and this year a large-scale pilot project backed by the Norwegian government will be built near Aqaba in Jordan. The Sahara Forest Project will combine different technologies to grow food and biofuel crops and be up and running by 2015.
But this is just one of many technologies being developed to enable food to be grown in unlikely places. One of the simplest, but most ambitious, plans may be the long-mooted Great Green Wall of Africa. This linear forest would be 15 kilometres wide and 7,775 kilometres long, and stretch from Senegal in the west to Djibouti in east Africa. It would, say the 11 countries through which it would pass, help to stop the southward spread of the Sahara, slow soil erosion and wind speeds, help rain water filter into the ground and create micro-climates to allow fruit, vegetables and other crops to be grown.
Insects
Locusts, grasshoppers, spiders, wasps, worms, ants and beetles are not on most European or US menus but at least 1,400 species are eaten across Africa, Latin America and Asia. Now, with rising food prices and worldwide land shortages, it could be just a matter of time before insect farms set up in places such as Britain.
Not only are many bugs rich in protein, low in fat and cholesterol and high in calcium and iron, but insect farms need little space. Environmentally, they beat conventional farms, too. The creatures are far better at converting plant biomass into edible meat than even our fastest growing livestock; they emit fewer greenhouse gases; and they can thrive on paper, algae and the industrial wastes that would normally be thrown away.
The advantages of “micro-livestock” farming are great, say the United Nations and European Union, both of which are keen to see if insect rearing could be greatly expanded. The Dutch government is studying how to set up insect farms. But aware of western squeamishness, they have asked researchers to see if they can just extract the protein that many bugs contain.
Meanwhile, the EU is offering its member-states three million euros [more than US$3.9 million] to promote the use of insects in cooking, and has asked food-standards watchdogs to investigate their potential to supplement diets.
http://www.guardian.co.uk/
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