Last month, the Hong Kong government released its long-awaited climate change strategy and 'action agenda'. Next month, it will host a conference of the C40 Cities Climate Leadership Group. As the government works hard to dress up Hong Kong's reputation for climate action, it should acknowledge some hard truths about the scale of the city's contribution to climate change. Today, the Social and Policy Research Unit of the Hong Kong Institute of Education, in collaboration with Civic Exchange, releases a report to help the government do just that. Chief Executive Donald Tsang Yam-kuen likes to claim that Hong Kong's greenhouse gas emissions are among the lowest in the developed world. It is true that the city's official reported emissions - just over 6 tonnes of carbon dioxide equivalent per person - are well below those of most developed countries. But these statistics are misleading. Because reported figures record only those emissions coming from within the physical territory of Hong Kong, they don't include some of our most polluting activities. For example, emissions from air travel and the production and import of food and goods are not counted. These exclusions hide the true size of our carbon footprint. How much climate pollution do we really cause? The simple answer is that we don't know. A recent study by the Norwegian University of Science and Technology estimated that Hong Kong's 2001 emissions would have been more than four times higher than was reported - equivalent to 29 tonnes of carbon dioxide - if emissions embedded in traded goods were counted. This places us among the world's biggest polluters. Conservation group WWF estimates that just one economy-class round trip between Hong Kong and London produces emissions equivalent to about 5.7 tonnes of carbon dioxide per passenger - roughly equivalent to the official annual emissions for each Hong Kong citizen. Yet more than six million return international flights taken by Hong Kong residents each year are not included in official pollution figures. Why does the Hong Kong government use misleading statistics? To be fair, the city's emissions inventory is calculated according to guidelines set by the UN Intergovernmental Panel on Climate Change. Under the panel's rules, only developed countries are required to report international aviation emissions. Because Hong Kong is part of developing China, the city is not required to report international air travel, and domestic travel (between Hong Kong and the rest of China) is conveniently added to China's total emissions rather than to Hong Kong's. International rules also stipulate that emissions are recorded where goods are produced, not where they are consumed. In most economies, there is a rough balance between emissions embedded in imports and exports, so these rules make some sense. But Hong Kong is an exception. Its reliance on imports means that agriculture and land-use changes, which account for more than one-third of many economies' climate pollution, barely figure on our balance sheet. What is more, most Hong Kong-owned manufacturing occurs over the border, meaning that emissions linked to Hong Kong's economy in the past now get added to China's total instead. It's no surprise then that Hong Kong's pollution statistics don't reflect our consumption patterns. Distorted emission statistics are creating distorted policies. Because energy production and energy consumption by buildings account for the bulk of Hong Kong's reported emissions, the government has targeted these areas for emissions reductions. Energy efficiency is vitally important, to be sure. But a sincere effort to reduce Hong Kong's carbon footprint requires a much wider focus. For example, as affluent people, many of us should be challenged to alter our consumption patterns, and we should take steps to limit the emissions caused by imports. Cutting back on flights is probably the single biggest contribution that those of us who travel can make. Reducing consumption of manufactured goods, meat (especially beef) and foods imported from far afield would also help to cut our emissions significantly. The upshot is that the Hong Kong government focuses on actions that will lower reported statistics, rather than on lifestyle changes that will most benefit the planet. However, if it wants to boast of low greenhouse gas emissions at the C40 conference, the government should be developing much more complete and accurate measures of our emissions - and encouraging us to act accordingly. Paul G. Harris is chair professor of global environmental studies, and Jonathan Symons is a post-doctoral research fellow, at the Hong Kong Institute of Education