The Doomsday Handbook Page 10
Can we stop it?
Monitoring and further research into the causes of bee decline will be the first step. In November 2010, scientists meeting at the Saint Louis Zoo in Missouri recommended that due to their low numbers, B. affinis, B. terricola and B. occidentalis should be listed on the Red List of Threatened Species compiled by the International Union for Conservation of Nature (IUCN). They also proposed the creation of a bumblebee specialist group within IUCN to help policy-makers and governments combat the population drops in bees.
Scientists at the University of Bristol are working on identifying hot spots of insect biodiversity in Bristol, Reading, Leeds and Edinburgh, in a bid to make cities more friendly to bees and other insects. They want to map everything from gardens to bits of wasteland, industrial estates and shopping centers to work out where there might be potential oases for pollinating insects.
Others are analyzing DNA from live wild bees in order to track how far and wide queen bees fly to start new nests, and how far worker bees go to look for food. Conserving populations means thinking about the number of nests and not just the number of individual bees—though there is a big challenge in that it is almost impossible to find bumblebee nests in the wild.
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These creatures contribute some $42 billion to the global economy.
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If the conservation efforts do not stem the tide, perhaps we will need to start looking for new pollinators to replace bumblebees. The US Department of Agriculture’s pollinating insect research unit at Utah State University has been studying the blue orchard bee.
Like honeybees, blue orchards can pollinate a variety of plants, including almond, peach and apple trees. They do not live in hives, however, preferring to spend their time in boreholes made in dead trees by other creatures, or in holes drilled into pieces of wood by people. And they are very effective: 2,000 blue orchards can do the work of 100,000 honeybees when it comes to pollinating blossoms on fruit trees.
Wherever the future lies, let’s hope the buzzing of the bees never goes away.
Invasive Species
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The Earth’s plants, animals and microorganisms have evolved together through a complex web of interactions over billions of years. Each of the world’s ecosystems is carefully balanced to keep its specific inhabitants alive. Insert something from outside, however, a plant or animal that nature never intended to be there, and all hell can break loose.
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Individuals of a species compete for food and space, animals hunt or hide from each other, microbes can be symbiotic or parasitic with other plants or animals. Over time, this interplay has created balanced ecosystems of diverse life all around the world, where different species can coexist without huge drama or sudden upsets.
Imagine what happens, then, if an invader encroaches on a balanced ecosystem. That invader could be a plant or animal that has not shared the co-evolution of the other myriad life forms already present in the ecosystem. If it were a predator animal, an aggressively growing plant or a pathogenic microbe, it would find easy pickings in a place where none of the species it encountered had evolved defenses against it. With no way of keeping the predatory behavior in check, the invader’s population would surge, and the once-balanced ecosystem would quickly destabilize toward collapse.
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COST OF INVASIVE SPECIES
$1.4 trillion per year to global economy
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“Ask an Asian rice farmer about a brown or green-coloured snail, some 10 cm in length, and you could well be asking about sinister creatures from Mars,” says Achim Steiner, executive director of the United Nations Environment Programme. “The golden apple snail has become a scourge in the paddy fields, damaging a staple crop as a result of its voracious appetite and costing a small fortune to control via environmentally questionable chemicals. The mollusc is among literally tens of thousands of life-forms classed as alien invasive species.”
Invasive species cost the global economy at least $1.4 trillion per year. They disrupt and destroy local ecosystems, transfer viruses around the world, poison soils and damage agriculture. And there is no stopping them.
What are invasive species?
The idea of invading creatures might bring to mind biblical plagues of locusts. Or perhaps the aliens that arrived to systematically destroy humans in H.G. Wells’ War of the Worlds. Each scenario is terrifying for its own reasons, but neither of them comes close to the current devastation caused as humans inadvertently spread species around the world and force meetings between organisms that were never meant to meet naturally.
In part, this is one of the side effects of our globalized world. More than 90 percent of trade is carried by sea, and the volume of traffic is set to double by 2018, with the global fleet increasing by 25 percent. In addition, hundreds of millions of sea passengers pass through European ports every year.
Increasing tourism and trade allows species to hitchhike between countries or continents on travelers’ baggage or clothes, or in freight or the ballast or waste water of ships. Plants and animals cling to the sides of ships in one country’s waters, ending up a few months later in the harbors and waterways of a country thousands of miles away. When fish started dying in their droves in the North Sea in the 1990s and 2000s, the deaths were linked to blooms of algae brought in by accident in the ballast water from the seas off China.
The golden apple snail was brought to Asia from South America in the 1980s as an aquarium pet and as gourmet food. When the snails did not sell, the importers released them into Asia’s lakes, and they have now spread to a dozen countries.
Traveling the other way around the world is the Asian long-horned beetle, which is normally endemic in Japan, Korea and China. The females of this species chew holes in the bark of hardwood trees (such as ash, maple, chestnut and willow) to lay eggs. When these hatch, the larvae bore further into the trunk and the damage they cause can kill the tree.
In recent decades, the beetles have been found in North America and Europe, imported via wood or wooden packaging. An infestation in northern Italy, caused by a single adult on four trees, required the felling of more than 300 susceptible trees in the vicinity in order to quarantine the pest.
Around ten new species become established every year in Europe, and there is a rising trend for invertebrates and fish to be introduced. According to a study on non-native species for the UK government, carried out by the environmental group CABI, the average time it takes for a species to get rooted in a new habitat is about 50 years, but this period is shorter in tropical species than in species from temperate regions. “In general, however, the rate of spread of [invasive species] is often exponential,” says the report.
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They disrupt and destroy local ecosystems, transfer viruses around the world, poison soils and damage agriculture. And there is no stopping them.
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Effects on biodiversity and ecosystem services
There are more than a billion hectares of hardwood forest in Great Britain. The government has estimated that if the Asian long-horned beetle became established in these forests, it would cost the economy more than £430 million. This includes the loss of income from infested trees as well as trees that have to be cut down to quarantine an area. For a country the size of the US, this figure jumps to a staggering $138 billion if the hardwood industry has to pack up because of beetle infestation.
Invasive plants can also destroy the way people live. “Take water hyacinth as one example,” says Steiner. “A native of the Amazon basin, it was brought to continents like Africa to decorate ornamental ponds with its attractive violet flowers. But there is nothing attractive about its impacts on Lake Victoria, where it is thought to have arrived in about 1990, travelling down the Kigera River from Rwanda and Burundi.”
Floating blankets of hyacinth, continues Steiner, have affected shipping, reduced fish catches, hampered electricity generation and had an effec
t on human health. “The plant has now invaded more than 50 countries around the world and annual costs to the Ugandan economy alone may be $112m. In sub-Saharan Africa, the invasive witchweed is responsible for annual maize losses amounting to $7bn. Overall losses to aliens may amount to more than $12bn in respect to Africa’s eight principle crops.”
Invasive species are acknowledged as one of the main pressures driving the loss of biodiversity around the world. “Of the 174 European species listed as critically endangered by the IUCN Red List, 65 are in danger because of introduced species,” says a 2010 report by the Institute for European Environmental Policy (IEEP). These include some of the most threatened species, such as the European mink and the ruddy duck. “The cumulative number of alien species is increasing for all groups including mammals, with one new alien mammal introduced per year. Similar patterns are observed in Europe’s marine environment.”
At the global level, says the IEEP report, invasive species have been identified as a key factor in 54 percent of all known extinctions documented by the Red List of endangered species, and the only factor in 20 percent of extinctions. “They are the second most important pressure on birds, impacting over half of species listed as critically endangered, the third most severe threat to mammals and the fourth to amphibians.”
Invasive species can also pose a health risk for humans. Cockroaches, for example, can carry pathogenic bacteria on to food and cause poisoning. “A survey by the Chartered Institute of Environmental Health in the Cossall Estate in London, which consists of 421 apartments contained in eight three-storey blocks with a history of cockroach infestation, found that 15.7 per cent of the apartments were infested. An estimated 59 per cent of English hospitals were reported to have cockroach infestations,” says the CABI report for the UK government.
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An estimated 59% of English hospitals were reported to have cockroach infestations.
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Economic costs
Invasive plants and animals can destroy local biodiversity and disrupt the food web. But they can also ruin agricultural crops and compromise key ecosystem services, such as pollination or keeping water clean, needed to sustain life or make money from the land.
In the Philippines, the golden apple snail is responsible for damage of up to $45 million to the annual rice crop. The IEEP report says that lost output due to invasive species, health impacts and expenditure to repair damage has already cost Europe at least 12 billion euros per year over the past 20 years.
More than $3.5 billion of crops are lost in the UK every year because of invasive pests and weeds. In the US, major environmental damage and losses from the 50,000 or so invasive species added up to almost $120 billion per year, according to a 2004 study by David Pimentel of the College of Agriculture and Life Sciences at Cornell University.
What can we do?
Some countries recognize the potential danger of invasive species and have tough rules on bringing foreign plants and animals across their borders. But according to Steiner, not enough places have really grasped the scale of the threat. The solution, he says, is to boost the capacity of customs, quarantine and scientific institutes able to provide early warning of invasive species, and this is particularly true for the world’s developing countries.
“Improved management of affected habitats can also assist,” he concludes. “There is some evidence that introducing a variety of native freshwater plants into a golden apple snail-infested site can reduce impacts on the rice crop ... As the economy recovers, global trade, including via shipping, will resume the risk of further invasions. Alien invasive species are part of the overall biodiversity challenge; for too long they have been given an easy ride.”
Desert Earth
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It has been called “the greatest environmental challenge of our time” and “a threat to global wellbeing” by a top UN official. It will displace millions, if not billions of people from their homes, cause wars and prevent people from growing the food they need to survive.
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The slow degradation of large swathes of the Earth into inhospitable desert is a natural process that occurs over millions of years as the climate shifts. But now, thanks to our treatment of the environment and the increase in greenhouse gases in the atmosphere, we are speeding this process up so that it is happening in the lifetimes of individuals, in parts of the world that can barely afford to deal with the consequences.
“The top 20 cm of soil is all that stands between us and extinction,” says Luc Gnacadja, executive secretary of the UN’s Convention to Combat Desertification (UNCCD). Healthy soil locks in a huge amount of carbon, and the organisms living in it are crucial for the growth of crops and forests. Gnacadja blames degradation and overuse of the land for conflicts seen in Somalia, dust storms in Asia and the increases in the price of food in recent years. A quarter of the planet’s land has been rendered useless since the 1980s, and this process continues at the rate of one percent per year today.
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Increased aridity is making the drylands the most conflict prone region of the world.
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According to the UN’s food and agricultural organization, 75 billion tons of soil, which equates to around 10 million hectares of arable land, is lost every year to erosion, waterlogging and salination. A further 20 million hectares is abandoned because its soil quality has been degraded.
And this is a problem that cannot be fixed quickly. Lester Brown of the Earth Policy Institute says that it takes up to 1,000 years to renew a layer of soil an inch thick. “The thin layer of topsoil that covers the planet’s land surface is the foundation of civilisation,” he says. “This soil, typically 6 inches or so deep, was formed over long stretches of geological time as new soil formation exceeded the natural rate of erosion. But sometime within the last century, as human and livestock populations expanded, soil erosion began to exceed new soil formation over large areas.”
With world populations on the increase, the pressure on land to produce ever more food will keep on rising. “Increased aridity is making the drylands the most conflict prone region of the world,” says Gnacadja. “If you really want to look at the root causes of the conflicts in Somalia and Darfur, and the drylands of Asia, you will understand that people in their quest to have access to productive land and water for life, they end up in conflict.”
How are deserts formed?
The great expanse of desert that covers a third of the Earth’s surface was formed by interactions between land and climate over millions of years. These drylands are home to more than 2 billion people, and the area has grown and shrunk as vegetation and rainfall have come and gone and humans have used or misused the land. “These arid regions are called deserts because they are dry,” according to the US Geological Survey (USGS). “They may be hot, they may be cold. They may be regions of sand or vast areas of rocks and gravel peppered with occasional plants. But deserts are always dry.”
Desertification is the process of degradation of land that has once been productive, as a farm or in supporting wildlife and forests. Deserts themselves grow and shrink naturally, and “areas far from natural deserts can degrade quickly to barren soil, rock, or sand through poor land management,” says the USGS. “The presence of a nearby desert has no direct relationship to desertification. Unfortunately, an area undergoing desertification is brought to public attention only after the process is well underway. Often little or no data are available to indicate the previous state of the ecosystem or the rate of degradation.”
Perhaps the best-known desertification in recent times occurred in the 1930s, when the Great Plains of the US turned into the “Dust Bowl” due to drought and overgrazing by livestock. More than 3.5 million people were forced to abandon their homes and livelihoods during this time. Nowadays, dust storms from the Gobi Desert in China blow into Beijing and surrounding countries, including South Korea. The biggest storms even reach North America.
Whe
n we try to remove too many resources—this includes excessive farming, diversion of water, grazing by livestock and building human settlements—the land will become unsustainable. “Increased population and livestock pressure on marginal lands has accelerated desertification,” says the USGS. “In some areas, nomads moving to less arid areas disrupt the local ecosystem and increase the rate of erosion of the land. Nomads are trying to escape the desert, but because of their land-use practices, they are bringing the desert with them.”
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Increased population and livestock pressure on marginal lands has accelerated desertification.
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It is also a misconception that droughts are at the root of desertification. Sure, dry conditions are common in at-risk places, but well-managed lands can recover from drought when the rains return, according to the USGS. “Continued land abuse during droughts, however, increases land degradation. By 1973, the drought that began in 1968 in the Sahel of West Africa and the land-use practices there had caused the deaths of more than 100,000 people and 12 million cattle, as well as the disruption of social organizations from villages to the national level.”