At the United Nations-organized climate change conference at Copenhagen, the debate about how to respond to climate change is moving towards its closing stages. Much of the debate has been about the responsibility that richer nations have in supporting poorer nations and agreeing on binding targets in controlling carbon emissions, thereby avoiding the devastation that will be wrought if global temperatures continue to climb at the current pace.

On the global scale, the health problems that are predicted to get worse if actions are not taken include food and water shortages, malnutrition, water- and food-borne diseases, deaths and injuries from flooding, and migration-related adverse health effects. The International Panel on Climate Change (IPCC) projects that global climate change through changing weather patterns will result in the increased risk of temperature-related mortality around the world. Periods of elevated temperature, in particular, are expected to contribute to a greater burden upon public health mortality and morbidity in both high- and low-income settings.

While some of these deaths would result from the impact from rising temperatures on the environment, many others will be directly due to the impact of changing temperatures on individuals. We will see more deaths and ill health related to extreme temperatures, especially for people older, chronically sick, very young, and socially isolated. International literature has shown that deaths in hot weather are most likely to be among the elderly and vulnerable populations, the trend that was evident in the summer of 2003 when tens of thousands of people died of hyperthermia from the extreme heatwave that swept across Europe.

Studies here in Hong Kong have mirrored this trend, confirming that patterns here are no different. As a major city in China, Hong Kong has one of the world's highest disparities in income and the highest average increase of urban ambient temperatures during the past century. In her study on the impact of heat on mortality in Hong Kong, Emily Chan, assistant professor of School of Public Health and Primary Care from the Chinese University of Hong Kong, found that intra-city variation of heat-related mortality varied with socioeconomic status among the Chinese population in Hong Kong, and that those living in poorer districts had higher death rates. She suggested the need for public health protection strategies for vulnerable population subgroups during elevated temperatures - particularly if we face increasing risks from climate change.

However, it is not just extreme heat but also cold that can impact the health of those vulnerable. Hong Kong is currently experiencing a sudden cold weather snap, leading to a warning issued by the Centre of Health Protection stating that the increased risks of cold weather to health require vulnerable groups to take extra care. Senior citizens and people with chronic medical conditions are particularly at risk, and are advised to adopt appropriate health measures to guard against the expected persistent cold weather in the coming days. The cold weather can certainly trigger diseases, especially among the elderly and people suffering from heart, respiratory, or chronic medical conditions. At this time, these vulnerable individuals are advised to take note of the weather forecast; wear appropriately warm clothing, including hats, scarves, gloves, and socks; consume sufficient food and drinks with a high caloric content, such as hot soup, rice, and noodles; stay in a warm environment and avoid exposure in open spaces; ensure safety in use of heaters, particularly by obtaining adequate indoor ventilation; and seek medical attention if unwell.

In addition to these recommendations, the Home Affairs Department has opened temporary cold shelters for those in need to avoid cases of hypothermia to those vulnerable to the weather. The first day of opening such shelter in December drew an approximate number of 300 citizens seeking refuge.

Looking back at the past few months, Hong Kong has certainly experienced sudden changes in temperature that are outside of the norm. While on a local scale the government appears to be well qualified in covering our needs to protect the health of our poor and vulnerable, permanent solutions to unusual temperature changes remain out of reach. Despite cultural differences and political undertones that have led to media frenzies and attempts to deviate from what matters most, participants at the Copenhagen conference no doubt can put aside their differences and agree on one thing: we as citizens of the world need a global solution that takes account of increasing hazards stemming from climate change and its impact on health, or risk irreversible and catastrophic damage to all.

The author is director of School of Public Health and Primary Care, Faculty of Medicine, the Chinese University of Hong Kong

(HK Edition 12/18/2009 page1)