Why carbon dioxide is both a blessing and a curse | Global Ideas | DW | 31.05.2011
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Global Ideas

Why carbon dioxide is both a blessing and a curse

Carbon dioxide might be a greenhouse gas, but it's not necessarily bad for the planet. Without it, there'd be no plant life and no human life as we know it. It's only toxic in high concentrations.

A close up of a green leaf

Carbon dioxide is essential to life as we know it

CO2 exists naturally in the Earth's atmosphere. As a greenhouse gas, it contributes to the Greenhouse Effect, the process by which thermal radiation from the planetary surface is absorbed by atmospheric greenhouse gases and re-radiated in all directions, thereby preventing the Earth from over-cooling.

Without this biosphere, life on earth as we know it would not be possible. Animals breathe in oxygen and breathe out CO2. Plants, meanwhile, breathe in CO2 and breathe out oxygen. So long as this cycle remains balanced, the system works.

The human hindrance

A car exhaust fumes

Human activity is unsettling the natural carbon cycle

Unfortunately, however, the balance is increasingly threatened.

"The concentration of CO2 in the atmosphere has risen dramatically since the dawn of industrialization," Friedrich-Wilhelm Gerstengarbe from the Potsdam Institute for Climate Impact Research (PIK) says.

The result is global warming. One contributing factor is the burning of fossil fuels such as coal, oil and gas. Another is the ongoing destruction of natural areas such as forests, which creates an imbalance in the carbon cycle by preventing their continued function as carbon sinks and laying waste to entire ecosystems.

When a cycle becomes a vicious circle

A palm oil plantation

The destruction of rainforest has far-reaching repercussions

The repercussions are far-reaching. Deforestation releases billions of tons of CO2, causing the greenhouse effect to go into overdrive, exacerbating global warming and sabotaging the natural habitats of plant and animal life.

Guenola Kahlert from the World Wildlife Fund organization for wildlife conservation and endangered species says the situation is alarming. "In terms of climate change, deforestation is a ticking bomb," she says, pointing out that it is responsible for up to 15 percent of greenhouse gas emissions. Compared to that, the share of emissions released by urban traffic is relatively low.

Kahlert is working on a project aimed at protecting Indonesia's peat bogs.

"Their degradation releases two billion tons of CO2 per year," she points out. That amounts to eight percent of global emissions caused by burning fossil fuels.

Agriculture and global warming

Dry forest

Dry tropical forest might be resilient but it's also vulnerable to climate change

The main reason for cutting forests is to make way for farmland and corn or palm oil production, for example.

"Humans create the demand and then commandeer the land they need in order to meet it,” says Guénola Kahlert. "These political decisions are made to the detriment of the climate."

The WWF climate expert believes that few decision-makers bother to take the longer view – and she doesn't see the problem restricted to Indonesia.

Rainforests are being destroyed all over the world. According to the WWF, the last decade has seen an area of rainforest the size of four soccer pitches disappear in the Amazon every minute – despite the region's key significance to the world climate.

Its rich vegetation and vast water resources not only protect the Earth from global warming but also store huge quantities of CO2 – experts estimate the amount to be equal to the amount of greenhouse gases emitted by human activities in a period of ten years.

In comparison, tropical dry forests are relatively robust CO2 sinks. although these too are by no means immune to global developments. Even though the tree species found in these forests display extraordinary adaptations to difficult climates – they survive without water for months on end, for example - they are nonetheless also vulnerable to climate change. Rising temperatures make these dry seasons even longer and take their toll on the forests' water resources.

But awareness of the importance of dry forests is growing. Germany has partnered with environmental groups in western Zambia, for example, to turn the Miombo woodlands in West Lunga into a conservation area in a move that will help the forests store an annual 13 million tonnes of CO2.

Incentives

The Miombo woodlands in Zambia

The Miombo woodlands in Zambia

Progess is occurring, confirms Guénola Kahlert. "Not all areas can be saved but we can at least salvage those that play a key role in terms of biodiversity, climate protection and mankind," she says.

But Friedrich-Wilhelm Gerstengarbe from PIK is less optimistic. "Time is running out and the evidence of climate change that we have seen so far is only the thin end of the wedge, if we continue with business as usual," he says. He strongly supports the idea of incentives and pins his hopes on international emissions trading.

According to this system, the world agrees not to exceed a specified level of carbon emissions in order to ensure global warming does not exceed 2 degrees by the year 2050. Countries that need to increase their emission permits must buy permits from those who require fewer permits.

"This is beneficial to both sides," says Gerstengarbe. "But it's first and foremost beneficial to the planet."

Author: Po Keung Cheung (jp)
Editor: Sonia Phalnikar

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