2015 may be the warmest on record, but heat waves will only intensify unless we act now
Gabriel Lau says research focusing on East Asia, North America and Europe shows that hot weather is likely to become more frequent and severe without action to address global warming, and coastal cities like Hong Kong will not be immune
The UN’s meteorological agency says the global average surface temperature in 2015 is likely to be the warmest on record. The Hong Kong Observatory believes this year will be the city’s warmest since records began in 1884. In India, a severe heat wave claimed the lives of more than 2,500 people in May. And, three months ago, Hong Kong experienced its hottest day on record.
The message is clear. Despite fluctuations, on a long-term scale, global temperatures are unquestionably rising. Hong Kong is beginning to feel the wrath of summer heat and the gradual blurring of the seasons.
Many scientific studies have concluded that this year’s sporadic weather pattern is not an aberration but a direct result of the sustained warming of our climate. The consequences are more than just the discomfort brought by hotter days. The extreme weather conditions experienced in many parts of the world may be linked to sustained climate change.
As a climate scientist, my current research on heat waves in East Asia (and two of my earlier studies focusing on North America and Europe) suggests that unless we act responsibly now, hot weather will prevail and intensify. Heat waves will not only become more frequent, but will last longer and be more severe. Coastal cities like Hong Kong will also be affected.
In 2012 and 2014, I collaborated with colleagues at the US Geophysical Fluid Dynamics Laboratory and the Chinese University of Hong Kong on two separate studies on extreme weather events in North America and Europe. This year, the research procedure and projections were repeated for East Asia.
These studies point to a consistent trend: as we head towards the end of this century, there are likely to be more than twice as many heat waves each year; and each is likely to last up to twice as long. These changes are equally likely in East Asia, Europe and North America.
In reaching our projections, we are already assuming that global-warming-contributing emissions will be reduced by half of the current level by 2080. Even with these efforts, the average global temperature will rise by about 2 degrees Celsius by 2100. If our energy consumption grows at current rates, the increase in emissions could easily push the temperature up by as much as 4 degrees, with even more extreme weather events.
Our most recent study suggests that if nothing is done to cut carbon emissions, the increasingly frequent severe heat waves that result would destroy crops in several sectors of East and Southeast Asia, causing widespread food shortages in the region. Hong Kong is unlikely to be spared. Temperatures of up to 40 degrees for several consecutive days in the summer could occur.
It is imperative that action is taken immediately to avert possible disaster on a global scale. A target of limiting the global temperature rise to 2 degrees by 2100 may look challenging, but it is achievable. What is crucial is a willingness on the part of the international community to cooperate, and reduce carbon emissions responsibly.
The Paris climate conference is an important platform, albeit a protracted process, for countries to set realistic and tangible targets, and to arrive at a set of policies and a collaboration framework. Individual governments need to play their part and adopt environmentally conscious development strategies.
In Hong Kong, certain policies could bring environmental benefits; emission reduction measures are the obvious choice. If energy consumption cannot be reduced significantly, a cleaner fuel mix should be pursued using natural gas and renewable energy, along with the promotion of green-building practises.
Intelligent city planning policies that allow better air circulation at street level would reduce the “heat island effect”, and the reliance on air conditioning. Encouraging mass transit travel would cut the number of private cars on the road, and the amount of emissions generated.
Small changes count. A switch to energy-saving appliances will save money and reduce fuel consumption and emissions. Even cutting meat consumption can make a difference.
Global warming is not a bluff. It poses an imminent threat. Unchecked greenhouse gas emissions will accelerate global warming with dire consequences. The heat waves that are closely linked to rising temperatures will become more frequent, more severe and last longer. Governments need to take the Paris meeting seriously – and act now for the sake of the next generation.
Professor Gabriel Lau Ngar-cheung is AXA professor of geography and resource management in the Faculty of Social Science, and director of the Institute of Environment, Energy and Sustainability, at Chinese University of Hong Kong