Fri, Sep 15, 2017 - Page 9 News List

Detailed assessment shows huge climate risks for Asia’s cities

By Hans Joachim Schellnhuber and Bambang Susantono

It is monsoon season in Asia, marking an end to months of scorching temperatures. However, the extreme heat will return, with cities facing particularly brutal conditions.

Already, Asia’s urban areas experience twice as many hot days as its rural areas do — and they could experience 10 times as many by 2100.

At that point, there will be no reversing the trend.

The first detailed assessment of climate risk for Asia, carried out by the Asian Development Bank and the Potsdam Institute for Climate Impact Research, makes clear that Asia’s cities stand at the front line of the fight against climate change.

Indeed, many consequences of a hotter planet — such as more extreme weather events, sea-level rise, environmental migration and mounting social tensions — intersect in urban areas.

This is particularly true in Asia, where cities house more than half of the population and produce nearly 80 percent of economic output. By 2050, Asia’s urban population could nearly double to 3 billion people.

Without new climate initiatives, the region’s cities could contribute more than half of the increase in global greenhouse-gas emissions over the next 20 years.

Such a scenario is often called “business as usual,” but in reality, it is business as usual that would be disrupted by the consequences of climate change, with unfettered warming impeding or even reversing Asia’s economic progress.

The longer the wait to address the climate challenge, the more devastating the disruption will be, and there might not be much warning, because climate effects generally do not evolve in a linear fashion, but emerge suddenly and powerfully once certain tipping points have been reached.

So far, not nearly enough has been done to assess Asia’s exposure to climate effects, much less to strengthen protections for vulnerable areas or reduce greenhouse-gas emissions.

The region needs low-carbon “green” growth strategies that use less land, water and energy. These strategies will help to slow rapid urbanization, which entails dense construction, sealed roads and private cars — all of which contribute to the “urban heat island” effect.

If the current path continues, the mean temperature over the Asian landmass could soar by more than 6?C — relative to pre-industrial levels — by 2100. People might fall ill and even die from respiratory and other ailments caused by heat stress or pollution.

Beyond the human costs, higher temperatures would undermine agricultural and industrial productivity.

Climate-driven migration flows will exacerbate the challenges Asian cities face. Unless a sufficient number of decent jobs are created, climate migrants could become a permanent underclass. Even if jobs are available, the environmental pressure created by ever-more populated cities would pose a grave threat.

However, projections of the effects of climate change on migration in Asia remain indefensibly limited in number, scope and predictive power.

To improve city planning and healthcare services, there must be a simple and accurate way to assess current and future heat-tolerance levels among urban populations.

Strategies are also needed to decrease urban heat stress, including a shift toward polycentric urban configurations, with economies and societies built around multiple regional hubs, rather than concentrated around a single city, and natural assets maintained through eco-corridors and connected green spaces.

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