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SCIENCE MATTERS by David Suzuki
“Rabid vampire bats attack Brazilian children” may sound like something out of the tabloid Weekly World News, but the headline actually ran in New Scientist, a credible and well-respected publication. Even weirder, the headline is true.
Vampire bats have indeed been attacking Brazilian children. In fact, they’ve bitten more than 1,300 people since September, and 23 of their victims have died from rabies. Beneath the sensational and bizarre story, however, lies more hopeful news about the emerging field of conservation medicine.
Conservation medicine is a relatively new discipline that refers to the convergence of ecology, which looks at species and ecosystems, and health science, which looks at the health of humans, plants, and animals. It’s a natural connection because the health of individual plants, animals, and people is intimately connected to the health of the ecosystems in which they are embedded.
What does this have to do with bats? Well, the reason for the recent increase in vampire bat attacks in Brazil is deforestation. The Amazon forests are being cleared for industry and agriculture, especially for grazing animals. With the loss of their homes, the bats are roosting closer to humans and they have a new, plentiful supply of slow-moving, warm-blooded prey: cattle. This has led to larger colonies of bats roosting in smaller areas, an ideal breeding ground for rabies, which makes the bats more aggressive and fearless of humans.
Rabies is not the only disease that has recently transferred to humans from bats. Bats are also a natural reservoir for SARS, the respiratory virus that caused panic in Toronto and tore through Southeast Asia two years ago. Originally, scientists thought civet cats were the reservoir for SARS, but they now believe bats infected the civets. Often, bats don’t eat all of their food. Fruit bats, for example, chew fruit to extract the sugars and then spit out the pulp, which is eaten by foraging animals below.
Scientists now believe that this is how the Nipah virus spread throughout pig farms in Malaysia five years ago, when farms began displacing forests and bats began roosting in barns. Authorities had to kill one million pigs and more than 100 farm workers died from the virus. More recently, in Bangladesh, the Nipah virus spread directly to humans when children picked and sold fruit that had been contaminated with partially digested bat dinners. Researchers also believe fruit dropped by bats may have spread the Hendra virus in Australia and the Ebola virus among primates in Africa.
Before we get out the pitchforks and torches to hunt down these winged terrors, consider what ecologist Andrew Dobson wrote in an analysis in the journal Science: “Assuming we can control these diseases by simply controlling bats is both naïve and short sighted. Instead, we must recognize that increased spillover-mediated pathogen transmission from bats to humans may simply reflect an increase in their contact through anthropogenic modification of the bat’s natural environment.”
In other words, as humans continue to modify and destroy bat habitat, we will continue to run into these problems. To solve them, we must focus on conservation and learning more about bat ecology and immunology, of which we currently know very little. Ultimately, minimizing the conditions that lead to disease outbreak is much more effective than dealing with the problem after it has occurred.
In nature, everything is connected. While people tend to think that human society is somehow excluded from nature – and we are merely observers – we are, in fact, deeply embedded in the natural world. Because of this, our actions can have profound, unforeseen, and mysterious repercussions. The new field of conservation medicine can both help us unlock those mysteries and help us build a healthier world.
Take the Nature Challenge and learn more at www.davidsuzuki.org
Kyoto: How does BC measure up?
British Columbia has been slow to address climate change in any meaningful way. The province’s current government released its climate change plan in December 2004, a full two years after releasing a broader energy plan. That energy plan focused on increasing the province’s reliance on fossil fuels, including boosting the production of oil and gas, and opening up the electricity system to more private and fossil fuel-based electricity, including coal-fired power.
BC’s climate change plan is weak, most notably because it does not set emission reduction targets, considering them “neither feasible nor meaningful at this time.” Emission reduction targets are set for agriculture and government operations, but these sectors are responsible for only six percent of the province’s emissions. No targets were set for the oil and gas sectors, road transportation, or electricity. In fact, the climate change plan reiterates the energy plan’s call to develop its “vast hydrocarbon reserves, “including coal, oil, and natural gas. In road transportation, promises are made for “strategic road infrastructure upgrades” and “strategic road improvements.” These vague terms were clarified in 2004 when the government announced its intention to twin the Port Mann Bridge and Highway 1 leading into Vancouver, a project that will greatly increase road traffic and air pollution in the Lower Mainland.
In 1973, the province established the Agricultural Land Reserve. The legislation is intended to protect agricultural land from development and keep urban sprawl from paving over land used to grow food. Though the legislation remains, the last two provincial governments have weakened and undermined it, using loopholes to remove important agricultural areas from protection.
As for electricity, the plan encourages a voluntary goal of having 50 percent of new electricity supply to come from “clean” sources, but BC’s definition of clean electricity includes natural gas and coal co-generation facilities and municipal solid waste incineration, all of which would be significant contributors to greenhouse gas (GHG) emissions.
The BC government has yet to sign an agreement with the federal government. The one area where the BC government’s energy plan could be lauded is with respect to energy efficiency. BC has suggested that it will update its Energy Efficiency Act to include more products and higher standards.
Recommendations:
• Develop a strong target for GHG emission reductions.
• Address GHGs from oil and gas production and transportation.
• Mandate that all new electricity come from low-impact renewables.
Strengths:
• Agricultural Land Reserve, which protects agricultural land from development and helps to contain urban sprawl.
• A promise to improve the energy efficiency of appliances.
Weaknesses:
• No emission reduction targets.
• A plan to expand Highway 1 into Vancouver, thereby increasing sprawl, road traffic, air pollution, and GHG emissions.
• A focus on expanding oil and gas production, including offshore, rather than addressing increasing emissions.
Missed opportunity:
• BC has access to a variety of renewable energy resources, including a world- renowned wind resource, but not a single wind power project.
Emissions:
BC’s greenhouse gas emissions increased 23.6 percent between 1990 and 2003. BC’s single greatest source of emissions is road transportation, mostly from personal vehicles. Those emissions have grown considerably due to a consumer shift from cars to SUVs and trucks. Emissions from light-duty trucks have doubled since 1990. This growth is only surpassed by the growth in emissions from the oil and gas sector.
Fugitive emissions – the inadvertent release of GHG from oil and gas production – are the greatest factor in this growth. Though BC’s electricity and heat sector (and the province as a whole) has had historically low emissions due to a large hydroelectricity base, these emissions have increased substantially since 1990. This is because the province has increased the share of power it gets using fossil fuels – mostly natural gas – rather than developing renewable sources of energy.
There is also increasing evidence that hydroelectric power may not be as climate-change-friendly as previously thought. Research has found that significant GHGs could be emitted from large-scale hydro dams due to the flooding of land and the creation of methane when vegetation decomposes. In fact, the Intergovernmental Panel on Climate Change has begun considering whether these emissions should be included in various countries’ GHG inventories. BC uses hydroelectric extensively.
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