Climate change is already contributing to sea-level rise and flooding. Droughts and storms are growing more intense. Ice caps are melting; snow cover is diminishing. And the ocean is becoming more acidic.
These changes threaten human food supplies, even as the global demand for food increases, and the problems can only be expected to worsen in the decades ahead, as will their ripple effects. A warmer planet with longer and more intense heat waves, for instance, doesn't just undermine farming. It also breeds disease.
That is the message the International Panel on Climate Change delivered yesterday in a report based on 12,000 scientific studies. The potential economic costs of these changes are staggering: The World Bank estimates it will cost $75 billion to $100 billion a year for adaptation measures in poor countries. And it is not difficult to imagine that the effects of climate change will contribute to greater levels of political instability around the world, as traditional forms of subsistence are undermined and battles over resources intensify.
It's all very alarming -- but not really new. If anything, this IPCC report is more cautious than the organization's 2007 report, which included greater detail about the scale and timing of the expected effects of climate change. So why has international cooperation on slowing, and adapting to, climate change been so long in coming?More specifically, why has it been so hard to get the world's biggest emissions producers to take responsibility for their actions? The European Union and nine countries -- led by China, the U.S., Russia, India and Brazil -- release 70 percent of the world's greenhouse gases. If they alone could cooperate to reduce emissions, the world could make enormous progress. But these countries have tended to view climate-change policies as if they were arms-reduction negotiations, with the major players saying, in effect: "We won't act unless you do."
That is not only short-sighted, but it is also self-defeating. Countries should tackle climate change out of self-interest. They need to reduce emissions and adapt to changes already under way in order to protect their own citizens and their own economies. Reducing emissions also brings immediate public health benefits, such as better air quality. And that creates economic benefits, because clean air helps draw workers and businesses. China's efforts to reduce pollution may reflect more a desire to attract talent and investment than to improve public health, but the two are related, and the end result is the same.
This September, world leaders are expected to report to the United Nations on how exactly they will work to help slow and, at the same time, adapt to climate change. It is essential that the big polluters come with plans to clean their own houses and offer some assistance to the poorer countries that stand to suffer disproportionately. Any that seek a free ride will end up paying a high price within their borders and imposing a terrible cost on the rest of the world.
--Editors: Francis Barry, Mary Duenwald.
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David Shipley at firstname.lastname@example.org