By Ricardo Lima

Special Report – Sea level in Macau “is now rising at an accelerated rate”

Scientists’ prediction for a medium-emission scenario is that by 2060 water levels will have risen 34 cm in Macau, about 20 per cent higher than the global average

MB September 2021 Special Report | Green Macau

The most recent study on the impacts of sea level rise (SLR) in Macau, published over a year ago, reveals that “global warming-related SLR constitutes a substantial threat to Macau, due to its low elevation, small size and ongoing land reclamation.”

Based on local tide gauge records, this study, originating from the Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, shows that sea level in Macau “is now rising at an accelerated rate”: with a mean rate of 1.35 mm/year over the period 1925–2010 jumping to 4.2 mm/year over 1970–2010, reflecting an apparent acceleration of SLR.

Furthermore, the document reveals that the sea level near Macau rose 10 per cent faster than the global mean during the period 1993–2012.

The scientific team led by Lin Wang states that “in the future, as projected by a suite of climate models, the rate of SLR in Macau will be about 20 per cent higher than the global average. This is induced primarily by a greater-than-average rate of oceanic thermal expansion in Macau, together with enhanced southerly anomalies that lead to a piling up of sea water.”

Specifically, the sea level is projected to rise between 8–12 cm by 2020, 22–51cm by 2060 and 35–118 cm by 2100 over the 1986–2005 baseline climatology, depending on the emissions scenario and climate sensitivity:

Sea level rise: the three scenarios

 2020 2060 2100
Lower-emission scenario 8 cm 22 cm 35 cm
Medium-emission scenario 10 cm 34 cm 65 cm
Worst case 12 cm 51 cm 118 cm

(Source: Sea Level Rise in Macau and Adjacent Southern China Coast: Historical Change and Future Projections, 2020)

“Global warming-related sea level rise constitutes a substantial threat to Macau, due to its low elevation, small size and ongoing land reclamation” – Lin Wang et al.

By Ricardo Lima

The key sources of the uncertainty, say the researchers, are the emissions scenario and poor knowledge of climate sensitivity. As we can see, by 2020, the uncertainty range is only 4 cm, but by 2100 the range increases to 83 cm.

A climate change report from 2019 by Climate Central indicated that the Pearl River Delta region, including Macau, Hong Kong and several major Chinese cities upriver, are especially vulnerable to flooding. According to the report, Mainland China is expected to be the country to suffer the largest impact, as by 2050 land that is now home to 93 million people could be lower than the height of the local average annual coastal flood. Climate Central’s projection map, considering the worst possible scenario by 2050, shows that most of the Macau Peninsula shoreline, Taipa, COTAI and almost the entirety of Henqgin would be at risk of flooding.

“Our results suggest that a region’s flood vulnerability is partly related to its level of socioeconomic development. The PRD region, which is less developed than Hong Kong, is more vulnerable to human costs (death and displacement),” according to Adam Switzer, another researcher, based in Singapore, who has been studying this issue. “With a rising sea level, the probability of extreme coastal flood disasters of high magnitude will increase significantly.”

So, the problem is not specific to Macau and affects the entire Pearl River Delta coast, as several other studies have warned. The only difference is the landfills. One of the rare scientific works on the subject, Energy Synthesis and Simulation for Macau (2006) by Kampeng Lei, Faculty of Science and Technology, University of Macau, and Zhishi Wang, Macau Science Centre, states: “Steady, sustainable reclamation of new land would be advantageous, but excessive reclamation will damage the city’s ecological health and weaken its sustainability. Thus, future reclamation should be carefully assessed from environmental and sustainability perspectives.”

When confronted with the impact of Typhoon Hato, which raised sea levels to record highs last seen in 1925, Transport and Public Works Secretary Raimundo do Rosário said: “Let’s review the landfills.”

Peak carbon dioxide emissions by 2030

Chief Executive Ho Iat Seng indicated last month that Macau will strive to reach peak carbon dioxide emissions by 2030, in conjunction with the country’s environmental development strategies.

“We will scrupulously promote measures relating to peak carbon dioxide emissions and carbon neutralization, and, taking into account the reality of Macau, we will implement the programme on a programmed basis, harnessing clean energy and striving to reach peak carbon dioxide emissions by 2030,” Ho said during his speech at the opening ceremony of the 12th International Infrastructure Investment and Construction Forum (IIICF).

(Chinese President Xi Jinping pledged at the 75th session of the United Nations General Assembly in September 2020 that China would reach its carbon emissions peak before 2030 and become “carbon neutral” before 2060.)

This seems to be Macau’s most impactful position on climate change.

In March 2015, the government created an interdepartmental working group on climate change. The group, led by the Secretary for Transport and Public Works, Raimundo do Rosário, and coordinated by the director of the Meteorological and Geophysical Bureau (SMG), held its first plenary meeting almost immediately. What has happened since then is a bit of a mystery.

Even before Ho Iat Seng revealed the commitment for 2030, Macau Business questioned the DSPA on what is being done regarding sea level rise.

“In line with the efforts to combat climate change determined by the country, and with regard to the main sources of greenhouse gas emissions in Macau, the Macau SAR Government will continue to implement the existing measures on energy conservation and reduction of emissions, namely in areas related to energy, transport and large companies, with the aim of promoting Macau’s low-carbon development,” was the reply they sent us.

In August, when he went to the Legislative Assembly, Secretary Raimundo do Rosário confirmed that the goal is to reach peak carbon emissions by 2030: “There is a goal that neither we nor the Mainland has defined, which is peak carbon emissions. We don’t promise anything. We define 2030 as the peak, but we don’t know how much this peak will be”, he affirmed, guaranteeing that “Macau will not lag behind the Mainland”.

Previous | GBA and the case for legal synchronization