The Ecology Book

331

See also: Global warming 202–203 ■ Pollution 230–235 ■ Urban sprawl 282–283

■ A plastic wasteland 284–285 ■ Renewable energy 300–305

ENVIRONMENTALISM AND CONSERVATION

Methane from landfill

After carbon dioxide, methane

is the most critical greenhouse

gas. Although its atmospheric

concentrations are lower than

CO 2 , methane is 25 times more

powerful at trapping heat in

the atmosphere. Atmospheric

methane comes from various

natural sources, including the

decay of vegetation in habitats

such as bogs and wetlands,

but also from livestock rearing,

from the use of fossil fuels,

and from the decomposition

of trash in landfill sites.

In many places, including

the UK and US, a number of

landfill sites are now trapping

and collecting methane

to produce energy. Landfill

gas contains up to 60 percent

methane, depending on the

composition of the waste and

the age of the site. Vertical

and horizontal pipelines are

placed through the landfill

to collect the methane, which

is then processed and filtered.

Most of it is used to generate

electricity, but it may also be

used in industry. After further

processing, it can be turned

into fuel for vehicles, too.

the world, recycling 99 percent of

household waste. About 50 percent

of this waste is burned in recycling

plants that generate heat for the

nation’s homes. Sweden also

imports waste from other countries

to process in its 32 incineration

plants. In 2015, it imported some

2.5 million tons (2.3 million tonnes)

of waste from Norway, the UK,

Ireland, and other nations.

“Mining” electronics

The fastest-growing type of waste

is discarded electronics. E-waste

from mobile phones, computer hard

drives, TVs, and other electrical

goods reached almost 46 million

tons (42 million tonnes) in 2014—

almost 25 percent more than in

2010. E-waste often contains
      precious metals, such as the gold,

silver, copper, and palladium used

in circuit boards. It has been shown

that “mining” landfill sites to

extract the metals can be more

cost-effective than mining natural

mineral deposits. However, e-waste

also includes toxic metals, such

as cadmium, lead, and mercury.

In countries that both generate and

import e-waste, landfill scavenging

for metals can be polluting. While

Europe now has an e-waste

reprocessing industry, relatively few

efficient schemes exist elsewhere.

There are many new initiatives,

but the world is still very far from

Connett’s zero waste ideal. A huge

challenge remains for individuals

and governments: cut consumption

and recycle global refuse that will

soon reach 2^1 / 4 billion tons (2 billion

tonnes) a year. ■

Methane is extracted at the

Payatas landfill, Manila—the first

in the Philippines to have the gas

converted to energy, as part of a

United Nations program.

Individual actions can

reduce waste—households

in the developed world add a

tonne of waste to landfill

each year.

Refuse plastic

bags and excessive

packaging. Buy products

in large containers or

without packaging.

Reuse what you

can or pass it on

to someone else

who can use it.

Recycle what

can’t be used so that

it can be turned into

new products.

Rethink as you shop.

Do you really need what

you are buying?

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