IPCC AR6 WG2 Demands We Build A Climate Resilient Northern Metropolis
By Chien Tat Low 23 March, 2022
HK’s new northern metropolis, slated to home 2.5mn & key to HK's food security, must adapt or risk being underwater. CWR’s Dr Low explains
“Adapt or die” – that’s the key message of the recent published IPCC AR6 WG2 report. We cannot afford to delay actions as the evidences have shown climate impacts not only are escalating and increasingly complex, but also reaching points of no return. This will have devastating consequences to Hong Kong if no holistic adaptation plans are in place.
This is particularly the case for Yuen Long, a key district of the Northern Metropolis that is well-known for its low-lying topography. It is also a hotspot for storm surge flooding, which we saw during Super Typhoon Hato in 2017 and Mangkhut in 2018. But luckily so far the flooding has been less than 5m.
Yuen Long, a key district of the Northern Metropolis, is a hotspot for flooding & was hit hard by recent super typhoons…
We say lucky because anything above 5m would impact key road links to the GBA – Lok Ma Chau and Sha Tau Kok. These 2 key road links in the Northern Metropolis carry almost 60% of cargo traffic between Hong Kong and Mainland China annually and are vital to Hong Kong’s food security as well as trade with the Mainland.
All of this is at risk in the not-too-distant future as multi-meter sea level rise (SLR) looms if we do not manage to limit warming to our Paris Agreement goal of 1.5°C by 2100. The alarms were sounded at COP26 because our current policies and action will lead us to end-of-century warming of 2.7°C, which means we must take the IPCC AR6’s warning seriously – that 2m of sea level rise (SLR) by 2100 and 5m by 2150 “cannot be ruled out due to deep uncertainty in ice sheet processes”.
…if the Northern Metropolis, slated to house 2.5mn people & key to HK’s food security, isn’t planned properly, it could be permanently lost
This has consequences – if we don’t plan properly the Northern Metropolis slated to house 2.5 million people would be permanently lost and the 3.8 million vehicles that pass through Lok Ma Chau and Sha Tau Kok annually that are vital for Hong Kong’s food security and economy would be stranded.
We must make sure this doesn’t happen. It’s not just SLR we should be worried about but also increasingly stronger storm surges and rainfalls that would bring compound and cascading risks across other sectors such as water, food, power, transportation, economic growth, and so on. Therefore, a transformational change is needed to ensure a climate-resilient Northern Metropolis in the future.
Rising Seas – 2m of SLR “cannot be ruled out”
Many still think SLR is far in the future, but it could happen sooner than we think. We have already warmed by 1.2°C today and the UN projects that we will likely reach 1.5°C by 2030, which is 70 years ahead of our Paris Agreement target. This means we will also feel the impacts from coastal threats sooner which is why the IPCC warned 2m of SLR cannot be ruled out by 2100.
2m of SLR will bring almost daily coastal flooding to 5-6m in HK…
…2 key road links to Shenzhen (Lok Ma Chau & Sha Tau Kok) will be underwater
With tides, 2m of SLR will bring almost daily coastal flooding to 5-6m in Hong Kong. This may seem high but this could have already happened as a one-off if Super Typhoon Mangkhut in 2018 hit Hong Kong directly and during high tide, what we are calling an “Unlucky Mangkhut”. As the map below shows, this would have huge implications for major transportation links – 2 key road links to Shenzhen (Lok Ma Chau and Sha Tau Kok) would be underwater.
Storm tides recede and cause temporary closure of major roads and public transport but rising sea levels are irreversible and will bring permanent disruption to our food security and trade.
SLR plus higher storm surges = 9m+ storm tides by 2100
SLR will only worsen the impact of storms. During Mangkhut the storm surge in Tai Po Kau was 3.4m causing a 4.7m storm tide. With SLR by 2100, the same storm surge at high tide would bring coastal flooding up to 8m and submerge 5 out of 6 key road links in Hong Kong. Only Heung Yuen Wai will be safe at this level.
But it gets worse because typhoon intensity is expected to increase – the IPCC warned that a Mangkhut-like typhoon will hit at least once every year by 2050 in most low-lying coastal cities. Recent research even predicts typhoons in Asia will become stronger and longer lasting with double the destructive power by the end of the century.
IPCC warned that a Mangkhut-like typhoon will hit at least once every year by 2050…
…so, by 2100 HK may have to protect against 9-11m of coastal flooding…
…typhoon-free SG is protecting against 5.5m, what is HK doing?
So, what if a typhoon stronger than Mangkhut hit when SLR is over 2m and at high tide? The answer is Hong Kong may have to protect against 9-11m of coastal flooding by 2100. By then all key road links to Mainland China will be underwater.
Now that we know what we face, Hong Kong needs to act sooner to avoid putting at risk millions of people’s lives and homes and wasting billions of dollars on badly planned projects. Others have already started – and it’s time for Hong Kong to follow suit.
Typhoon free Singapore is prioritising adaptation as it recognises the consequences of not acting so it is raising critical infrastructure by 5.5m to protect the island nation. Hong Kong’s neighbour Shenzhen also upped its protection to 6-8m post-Mangkhut; these levels are higher than Singapore’s as it is also typhoon prone like Hong Kong. As the Northern Metropolis seeks integration with Shenzhen, Hong Kong must plan now to make sure its key road links to Mainland China are protected.
Will new transport infrastructure also be underwater?
While existing key road links are at risk from coastal threats, the Hong Kong government is planning to build five new railway links with Mainland China to boost the economy in the Northern Metropolis. According to the map above, it appears that some of these proposed railways will also be at risk with 2m of SLR or if Unlucky Mangkhut hit us today. Is the government prepared enough to avoid this new infrastructure going underwater?
And let’s not forget about the existing MTR stations. Most MTR station entrances were built 450mm above street level and they are equipped with a 1.2m high flood board, which has worked well so far as Hong Kong has yet to witness major flooding. However, with advancing climate threats, perhaps it’s time to redesign the flood prevention measures for all existing and new MTR stations, railway lines and electronic installations?
Know what will kill us and how to keep us alive
It’s great that Hong Kong now strives to achieve carbon neutrality by 2050. But it is equally important for Hong Kong to fast track adaptation because it is tracking the worst-case scenario projections.
It’s not just rapid SLR that we will have to contend with, but we must also prepare for hotter days and flash floods from more extreme rains, plus there may come a day when our skyscrapers can no longer withstand rising typhoon wind speeds. To build a climate resilient Northern Metropolis, we need a grand redesign of Hong Kong buildings, transport and critical infrastructure.
HKSAR gov’t should heed the IPCC’s AR6 WG2 for transformative adaptation that considers worst case scenarios…
Obviously, the HKSAR government should definitely heed the IPCC’s AR6 WG2 because its vulnerability to coastal threats offers an opportunity for transformative adaptation. The good news is that unlike the existing heavily developed urban areas along the Victoria Harbour, there is much more flexibility to build climate resilience into the Northern Metropolis. To start, it’s prudent to start assessing the impacts of the worst-case scenario so that we know what will kill us and adapt flexibly so that one of Hong Kong’s biggest infrastructure projects will thrive for decades even if the worst happens.
If you want to know more about how to build a resilience roadmap, click here.
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