Daily Archives: December 21, 2007

Population is key to cutting emissions

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Michael Backman in his latest Age column writes about the issue of population and its connection to greenhouse gases.

WHAT is the ultimate cause of greenhouse gases? Excessive reliance on cars? Coal-fired power stations? Clear-felling forests? The answer is none of these. The ultimate cause is people and population growth.

Having one child with your partner instead of two or more is the biggest contribution to reducing greenhouse gases you can make. Have one child instead of two and you will be directly responsible for cutting your family’s greenhouse gas emissions by about 50% in the next generation.
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Determining which countries have been responsible when it comes to population growth generates a different picture when it comes to developing countries. China is a big and growing greenhouse gas emitter. But it has one of the lowest population growth rates in the region due to the success of its one-child policy and also due to its rising wealth levels — richer people tend to have fewer children.

India, on the other hand, is not yet as big a gas emitter as China. Gas emissions per head are about three times less — but its population is growing much faster than China’s. Its population will overtake China’s in the 2030s, when both countries can be expected to have populations of about 1.5 billion. But South Asia, taken as a whole, is already the clear winner in the population stakes. Had partition not taken place in 1947, then India would have overtaken China for the No. 1 spot years ago. The combined population of pre-partition India today (India, Pakistan and Bangladesh) is 1.4 billion, compared with China’s population of 1.3 billion.
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Indeed, the population of pre-partition India is expected to rise by another 900 million people in the first half of this century. Changing to energy-saving light bulbs will be a drop in the ocean compared with this

Cities and Warming

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Bjorn Lomberg makes some interesting arguments on how cities around the world are experiencing high temparature rises, are coping with and what possible low-cost solutions would be.

Most of the world’s urban areas have already experienced far more dramatic temperature hikes over the past few decades than the 2.6°C increase expected from global warming over the next hundred years.
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Today, the fastest-growing cities are in Asia. Beijing is roughly 10°C hotter than the nearby countryside in the daytime and 5.5°C warmer at night. There are even more dramatic increases in Tokyo. In August, temperatures there climbed 12.5oC above the surrounding countryside, reaching 40oC – a scorching heat that affected not only the downtown area, but also covered some 8,000 square kilometers.

Looking at a fast-growing city like Houston, Texas, we can see the real effect of the urban heat island. Over the last 12 years, Houston grew by 20%, or 300,000 inhabitants. During that time, the night time temperature increased about 0.8°C. Over a hundred-year period, that would translate to a whopping 7°C increase.
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Even as temperatures have risen, heat-related deaths have decreased, owing to improved health care, access to medical facilities, and air-conditioning. We have far more money and much greater technological ability to adapt than our forebears ever did.
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These options are simple, obvious, and cost-effective. Consider Los Angeles. Re-roofing most of the city’s five million homes in lighter colors, painting a quarter of the roads and planting 11 million trees would have a one-time cost of about $1 billion. Each year after that, this would lower air conditioning costs by about $170 million and provide $360 million in smog-reduction benefits. And it would lower LA temperatures by about 3°C – or about the temperature increase envisioned for the rest of this century.