We must focus on big picture of man-made global warming

PUBLISHED : Wednesday, 24 August, 2016, 4:02pm
UPDATED : Wednesday, 24 August, 2016, 11:25pm

I refer to the letter by Wyss Yim (“Carbon dioxide reduction only partial solution”, August 14) in reply to my letter (“Established laws of physics used to make climate projections”, August 4).

Long records of climate data are crucial to climate change studies and the century-long temperature records taken at the Observatory headquarters in Tsim Sha Tsui clearly display a warming trend in Hong Kong, both as a result of global warming and local urbanisation effects.

Data from rural stations with sufficient length of records, such as Waglan Island and Cheung Chau, also show long-term warming trends.

Your correspondent’s queries pertaining to sea-level rise in Hong Kong, such as the issues of data continuity at North Point and Quarry Bay, and the general observation of rapid sea level rise in 1987-1999, have all been examined, explained and documented (www.hko.gov.hk/publica/reprint/r990.pdf). The mean sea level data shown in our climate change pamphlet and webpage have been corrected for land settlement for the purpose of long-term trend analysis (www.hko.gov.hk/climate_change/obs_hk_sea_level_e.htm).

Wyss Yim also tends to overstate the climatic effects of volcanic activity. The cooling effect of volcanic eruptions is short-lived compared to the warming effect of long-lived greenhouse gases. In the absence of scientific proof, it still requires quite some imagination to conclude that the Chaitén volcano in Chile, being over 17,600km from Hong Kong, could have an effect on local rainfall recorded here.

As I have mentioned in previous letters, it is a clear scientific consensus that the increasing atmospheric greenhouse gas concentration is the culprit of global warming in the recent century or so.

Wyss Yim may dwell on his subjects of interest for as long as he likes, but one wonders why he chooses to persistently and inordinately play up his pet topics to mask the profoundly more important big picture of man-made global warming. It is currently impacting the climate and environment, and will continue to do so for generations to come if carbon emissions remain unchecked.

Lee Sai-ming, senior scientific officer, Hong Kong Observatory