DURBAN CLIMATE CHANGE CONFERENCE: A paper published yesterday shows global industrial emissions of carbon dioxide, overwhelmingly from fossil fuels, jumped by 5.9% from 2009 to 2010. This is a big increase, far exceeding the average growth rates in the 1980s (2.0% per year), the 1990s (1.0% per year) and 2000-2009 (3.1% per year).
Why the fuss? Carbon dioxide (CO₂) is the most important of the atmospheric greenhouse gases responsible for human-induced climate change. (Water vapour, although an important greenhouse gas, is not significantly influenced directly by human activities).
To keep climate change within tolerable bounds, the biggest single challenge is to reduce CO₂ emissions – and yet there is renewed growth in the dominant CO₂ emissions source: fossil fuel combustion.
To reverse this emissions juggernaut we must first understand it. It is useful to look at past patterns over three different time periods: two centuries, two decades and two years.
A view over two centuries reveals fundamental relationships between economic growth, energy and fossil fuel consumption. Past and present economic activity is closely coupled to energy use by human societies.
This energy has been supplied mainly from fossil fuels since the Industrial Revolution of the 18th and 19th centuries. Affluent nations have a history of high energy and fossil fuel consumption per person.
The picture over the past two decades is consistent with these fundamental relationships, but also shows a profound transition. The great driver has been intense economic growth in the developing world – prominently in China and India but in many smaller nations as well – powered by energy that is still largely sourced from fossil fuels.
In 1990, developed or industrialised nations – comprising just 20% of the world’s population – accounted for 65% of fossil fuel CO₂ emissions. By 2010 the share of emissions from the same developed nations was just 42% of the global total, because of rapid growth in emissions from developing nations.
Two decades ago, emissions per person in developed nations were a massive 7.5 times those of developing nations, but that ratio has now halved to 3.8. The world is still a very long way from equality, but it is converging in terms of economic wealth, energy consumption and CO₂ emissions.
At the two-year time scale, the huge 5.9% global growth in CO₂ emissions from 2009 to 2010 has wiped out the small decrease of 1.3% that occurred from 2008 to 2009, associated with the Global Financial Crisis (GFC). Both developed and developing nations participated in this emissions rebound. Three causes can be identified:
A rapid easing in energy prices through the GFC lessened pressures for energy efficiency.
Many countries responded to the GFC with major government investment that boosted economic activity and emissions.
The previous decade of high economic growth in the developing world provided the foundation for a rapid post-GFC economic recovery, propagating into high emissions growth.
The rate at which the emissions efficiency of the global economy (the dollars earned per kilogram of fossil carbon burned to produce energy) is improving has also slackened. For several decades, this efficiency has increased at about 1.5% per year: greater efficiency makes economic sense. That said, the rate of improvement has weakened over the past few years as the share of coal has increased in the global fossil fuel mix. From 2009 to 2010, efficiency actually decreased.
In a connected, globalised world, all nations are aboard the emissions juggernaut. Both economic and climatic futures are inextricably entwined between nations. Continuing increases in emissions will lead to severe impacts on climate, ecosystems, and the services they provide to human societies. Five implications are now clear:
Rapid reductions in greenhouse gas emissions are necessary to keep climate change to tolerable levels for ecosystems and humans. A warming of 2°C from pre-industrial temperatures is the internationally agreed limit.
The biggest challenge is reducing global CO₂ emissions from fossil fuels, which need to decrease at an average rate of about 3% per year for the rest of this century, starting within a few years. Delay will increase the required rate rapidly.
The required reductions cannot be achieved without participation of both developed and developing nations.
Major emissions reductions need to be consistent with maintaining quality of life, and improving it in presently developing and underdeveloped nations.
This requires much accelerated improvements in energy efficiency. New technologies and changes to consumption patterns are both essential.
These challenges apply not only for the negotiators in Durban this week, but for nations and individuals as well.