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

HK's critical northern metropolis is a hotspot for severe flooding & typhoons and so it is time to 'adapt or die', the key message of the recently published IPCC AR6 WG2 report
2m of SLR will bring almost daily coastal flooding to 5-6m in HK at which point 2 key road links to Shenzhen will be underwater; by 2100, may need to protect against 9-11m
HK should heed the IPCC’s warnings for transformative adaptation in Northern Metropolis = protect the existing & new transport infrastructure e.g. MTR & the 5 new railway links

“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.

Further Reading

  • 3 First Steps To Protect HK From Rising Seas – The IPCC AR6 warnings on rising seas bring bad tidings for Hong Kong. If you are 20 & younger, HK could become the new Atlantis in your lifetime unless we take action now. See 3D maps of areas submerged and get on top of what you need to do to survive, adapt & thrive
  • Hong Kong Is Tracking Worst-Case Scenario Impacts – 8 Reasons To Act Now – With this summer of rising climate risks, don’t get caught out. CWR’s Chien Tat Low & Debra Tan run through 8 reasons why Hong Kong must act now to get on top of advancing climate threats – from hot weather, strong winds to flash floods – be prepared!
  • Designing Resilience – 2 Architectural Students’ Take on Coastal Threats – Shocked by HK’s coastal threat, HKU’s Fergal Tse & Oscar Wong became CWR’s interns to re-design Victoria Harbour. We sit down with them to understand what local youths think about climate change and & their projects with CWR changed their perspective
  • HK Submerged? Is This Map For Real? – Rising sea level is a catastrophe waiting to happen but we have to avoid alarmism & choose the right map to visualise the risks. Getting the right scenarios also matter. Find out more in our review
  • 8 Asia Water Risks: Here Today & Here To Stay In Asia – Damaging typhoons, life & business disrupting water outages and threatening sea level rise… China Water Risk review’s 8 water threats too great to miss in Asia from just the past 3 years
  • Chinese Port Organisations on Adaptation – Ports are a key economic drivers but rising sea levels are putting them at risk. Are Chinese ports taking action? Find out in our review

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Chien Tat Low
Author: Chien Tat Low
Low has extensive inter-disciplinary research experience, which although wide-ranging, focuses on identifying hotspots to facilitate better planning. At CWR, Low uses spatial modelling and statistical analysis as well as remote sensing, cartography, and geo-statistics to map and assess water risks. In addition, he helps manage CWR’s extensive network of contributors and partners. CWR is Low’s first foray outside academia and he hopes to apply his 12 years of scientific know-how toward enhancing the understanding of water risk in Asia, including spatial temporal variabilities of anthropogenic and natural factors on water resources. Previously, Low was a postdoctoral fellow at the University of Hong Kong where he devised methodologies to measure and benchmark the quality of urban life in an Asian context. As a certified GIS Professional, he also taught GIS and spatial analysis modules there. Low’s research on urban, human and environmental health is published in 11 prominent international peer-reviewed journals; he has also written a chapter in a book on managing environmental hazards. His PhD thesis on place effect on human well-being was prize-winning. Low is currently the reviewer editor for the journal “Frontiers in Environmental Informatics” and also reviews other international journals such as “Applied Geography”.
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