TWENTY-FIVE
PEOPLE IN GREENHOUSES
SHOULDN’T TELL LIES

The opposition to reducing emissions of greenhouse gases is most intense in the US. The American energy sector is full of cashed-up businesses that use their influence to combat concern about climate change, to destroy emerging challengers, and to oppose moves towards greater energy efficiency.

In the 1970s the US was a world leader and innovator in energy conservation, photovoltaics (converting light to energy) and wind technology. Today it lags behind other countries in these areas. Over the past two decades some in the fossil-fuel industry have worked tirelessly to prevent the world from taking serious action to combat climate change.

The US coal producers have been centre-stage in this campaign. In the 90s Fred Palmer, now company vice-president at Peabody Energy, the world’s largest coal producer, led a campaign that the Earth’s atmosphere ‘is deficient in carbon dioxide’. Producing more would bring in an age of eternal summer. Rather like the CEO of an arms manufacturer arguing that a nuclear war would be good for the planet, Peabody Energy wanted to create a world with atmospheric CO₂ of around 1000 parts per million.

Palmer’s views were the basis for the propaganda video The Greening of Planet Earth which promoted the idea of ‘fertilising’ the world with CO₂ to boost crop yields by 30 to 60 per cent, thus bringing an end to world hunger. While such ludicrous claims could be laughed off by scientists, many people were misled.

On the other hand, some fossil-fuel companies are playing an active role in combating climate change. BP, for instance, has taken a clear-eyed view of climate change and has moved ‘beyond petroleum’, making a 20 per cent cut in its own CO₂ emissions, and a profit in doing so. BP has now become one of the world’s largest producers of photovoltaic cells.

The British Prime Minister Tony Blair has a firm grasp of the science surrounding the issue. He has described global warming as ‘a challenge so far-reaching in its impact and irreversible in its destructive power, that it alters radically human existence…There is no doubt that the time to act is now.’

By 2003 Britain’s CO₂ emissions had fallen to 4 per cent below what they were in 1990. Significant milestones of this period include the establishment of the Carbon Trust (which helps business address energy use), an obligation by power suppliers to provide 15.4 per cent of their energy from renewable sources, and significant investments in developing wave and tidal power. Britain is also considering expanding its nuclear power capacity.

These debates about how to transfer from fossil fuels to renewable sources of energy will only grow more intense.

Can we find solutions to the problem of global warming while continuing to use fossil fuels?

The coal industry is promoting the idea of pumping CO₂ underground in order to take it out of the atmosphere. The process, known as geosequestration—it means hiding in the earth—is simple in its approach: the industry would bury the carbon that it had dug up.

Oil and gas companies have been pumping CO₂ underground for years. A good example is the Norwegian Sleipner oilfield in the North Sea where about a million tonnes of CO₂ is pumped underground each year. The Norwegian government has placed a US $40 per tonne tax on CO₂ emissions. This provides the incentive at Sleipner to separate out the CO₂ that comes up with the oil and pump it back into the rocks.

At a few other wells around the world, the CO₂ is pumped back into the oil reserve, helping to maintain head pressure, which assists with the recovery of oil and gas, making the entire operation more profitable. The companies claim ‘most’ of the CO₂ stays underground. Applying this model to the coal industry, however, is not straightforward.

The problems for coal commence at the smokestack. The stream of CO₂ emitted there is relatively dilute, making its capture unrealistic. The coal industry is promoting a new process known as coal gasification, which creates a more concentrated stream of CO₂ for capture and burial. These plants are not cheap to run: around one quarter of the energy they produce is consumed just in keeping them operating. Building them on a commercial scale will be expensive and it will take decades for them to make a big contribution to power production.

Let’s assume that some plants are built and the CO₂ they emit is captured. For every tonne of anthracite burned, around 3.7 tonnes of CO₂ is generated, all of which must be stored. The rocks that produce coal are not often useful for storing CO₂, so the gas would have to be transported away from the power stations. In the case of Australia’s Hunter Valley coal mines, for example, it would need to be carried over Australia’s Great Dividing Range and hundreds of kilometres to the west to a suitable site.

Once the CO₂ arrives at its destination it must be compressed into a liquid so it can be injected into the ground—a step that typically consumes 20 per cent of the energy yielded by burning coal in the first place. Then a kilometre-deep hole must be drilled and the CO₂ injected. From that day on, the geological formation must be closely monitored. If the gas were ever to escape, it has the potential to kill.

Miners used to call concentrated CO₂ ‘choke-damp’, an appropriate name as it instantaneously smothers its victims.

The largest recent disaster caused by CO₂ occurred in 1986, in Cameroon, central Africa. A volcanic crater-lake known as Nyos belched bubbles of CO₂ into the still night air and the gas settled around the lake’s shore. It killed 1800 people and countless thousands of animals, both wild and domesticated.

No one is suggesting we bury CO₂ in volcanic regions like Nyos, so the CO₂ dumps created by industry are unlikely to cause a similar disaster. Still, Earth’s crust is not a purpose-built vessel for holding CO₂, and the storage must last thousands of years. The risk of a leak must be taken seriously.

The amount of CO₂ we would need to bury is mind-boggling. We can use a country like Australia, with its comparatively small population, as an example. Imagine a pile of 200-litre drums, ten kilometres long and five kilometres across, stacked ten drums high. That would be more than 1.3 billion drums, the number required to hold the CO₂ that pours out of Australia’s twenty-four coal power stations, which provide power to 20 million people every day. Even when compressed to liquid form, that daily output would take up a third of a cubic kilometre, and Australia accounts for less than 2 per cent of global emissions!

Imagine injecting 20 cubic kilometres of liquid CO₂ into the Earth’s crust every day of the year for the next century or two.

If we were to try to bury all the emissions from coal, the world would very quickly run out of A-grade reservoirs near power stations. There are enough fossil fuel reserves on planet Earth to create 5000 billion tonnes of CO₂. How could Earth tuck that away without suffering fatal indigestion?

The best-case scenario for geosequestration is that it will play a small role (at most perhaps 10 per cent by 2050) in the world’s energy future.

There are other forms of sequestration—of hiding carbon—which are vital for the future of the planet, and which carry no risk. Earth’s vegetation and soils are reservoirs for huge volumes of carbon, and are critical elements in the carbon cycle. Today the world is mostly deforested and its soils exhausted, but soil carbon can be enhanced by following sustainable agricultural and animal farming practices.

This increases the vegetable mould (mostly carbon) in the soil. Lots of carbon—around 1180 gigatonnes—is currently stored this way; more than twice as much as is stored in living vegetation (493 gigatonnes). There is real hope for progress here, in initiatives that include everything from organic market gardening to sustainable rangelands management.

Can we store carbon in forests and long-lived forest products? This involves either planting forests, or preserving them. The Costa Rican government saved half a million hectares of tropical rainforest from logging. This brought it carbon credits equivalent to the amount of CO₂ that would have entered the atmosphere if the forests had been disturbed.

Another example is BP’s initiative to fund the planting of 25,000 hectares of pine trees in Western Australia to offset emissions from its refinery near Perth.

Forestry plantations are destined to be cut and used, but they can be a good short-term store for carbon because the furniture and housing they produce are long-lived, and because the roots of the felled trees (along with their carbon) stay in the ground.

The carbon in coal has been safely locked away for hundreds of millions of years, and will remain there for millions more if we refuse to dig it up.

Carbon locked away in forests or the soil is unlikely to remain out of circulation for more than a few centuries. By trading coal storage for tree storage of carbon, we are exchanging a long-term guarantee for a quick fix.

Scientists continue to work on the problem of safe, secure storage for carbon, and perhaps a solution will eventuate. Meanwhile, the competition from less carbon-dense fuels is looking simpler and cheaper by the day.