On Thin Ice! 5 Hot Trends for Rising Seas

By Chien Tat Low 23 February, 2022

What's the latest on sea level rise after the IPCC-AR6 report? CWR's Dr Low shares 5 trends you can't afford to miss

The Arctic continues to warm 2x faster than the rest of the world but some worry it is likely 4x faster; Artic summer hit 38°C & the first ever rain was observed in Greenland
Extreme heat in oceans passed ‘point of no return’ & 2021 was the hottest year yet; meanwhile, the Thwaites Glacier Ice Shelf could shatter in 5 yrs = rapid sea level rise
Atmospheric methane is growing 'dangerously fast' – worrying potential new feedback loop; CO2 emissions dip during COVID just a blip; only a matter of time for low-lying cities

2021 was the seventh hottest years consecutively since 2015. It will also be remembered as a year with a series of extreme weather events including wildfires, droughts, floods and storms around the world, sounding alarm bells on accelerated changing climate. Indeed, the new IPCC AR6 report stated unequivocally that we have caused our world to warm and has warned of code red for humanityon a variety of existential threats.

The reality could be even worse than we think if we don’t rein in carbon emission quickly. More grim news and research show that climate threats, especially rising seas, continue to advance after the release of IPCC-AR6 report, which is why we cannot afford to delay adaptation planning and action. In the spirit of 5 trends of the Year of the Tiger, we have picked the following 5 hot trends for sea level rise that you can’t afford to miss.

1. Warming faster than you think – Arctic summer is hot as the Mediterranean

The state of the Arctic is not looking good according to the 2021 Arctic Report Card. The Arctic continues to warm more than twice as fast as the rest of the globe. The global average temperature has risen by 1.2°C since the pre-industrial period, while in the Arctic region it has warmed by more than 2-3°C.

Arctic continues to warm 2x faster than the rest of the globe; some studies showed it is likely 4x faster

And actually, recent research shows that Arctic is actually now warming four times as fast the rest of the globe. This means that many scientific journals and assessment reports including the IPCC AR6 have been underestimating the Arctic warming rate by a factor of two – which is worrisome!

According to the 2021 Arctic Report Card, the average surface air temperature over the Arctic during October 2020 to September 2021 was the seventh warmest on record, which is the eighth consecutive year since 2014. The heating in the Arctic is driving massive loss of sea ice, the Greenland Ice Sheet and snow cover. It also yielded some unprecedented impacts including the first rainfall observed at Greenland’s summit.

On 20 June 2020, the WMO recorded a record high temperature of 38°C in the Russian town of Verkhoyansk, which is located 115 kilometres north of the Arctic Circle. The WMO said that this extreme temperature was “more befitting the Mediterranean than the Arctic”, sounding alarm bells about our changing climate.

Sadly, what happens in the Arctic doesn’t stay in the Arctic. The changing climate in the Arctic will have profound impacts globally. While the temperature rise is causing massive loss of sea ice, our ice-free ocean is absorbing more direct heat from the sun and getting hotter. As a result, it accelerates the melt of the Antarctic Ice Sheet and causes rapid sea level rise, which brings us to the next trend.

2. Extreme heat in ocean has passed ‘point of no return’ – 2021 was the hottest year yet

Indeed, the ocean in 2021 was the hottest ever recorded by humans. The amount of heat going into the oceans in 2021 was 235 zettajoules, which is more than 2020 by 14 zettajoules. For perspective, the rate of ocean warming in 2021 is equivalent to denoting seven Hiroshima atomic bombs every second. This is higher than the average number of five atomic bombs per second in the past 25 years.

Extreme temperatures occurring just 2% of the time a century ago have occurred at least 50% of the time across global oceans since 2014

Other researchers report that extreme heat in our ocean passed a “point of no return” in 2014 and so this increasing ocean temperatures has been the new normal. Their research found that extreme temperatures occurring just 2% of the time a century ago have occurred at least 50% of the time across global oceans since 2014. The researchers defined the “point of no return” when the year has more than 50% of surface areas exceeded and remained above the 1870-1919 threshold.

Why worry? The hotter ocean temperatures are fuelling the ice loss in the West Antarctica and could cause an abrupt jump of sea level rise.

3. West Antarctic is losing ice faster than ever – ice shelf holding Thwaites Glacier could shatter in 5 years

The Thwaites Glacier, a critical glacier in Antarctica with the size of Florida, is responsible for about 4% of global annual sea level rise as it slowly melts into the ocean. However, scientists warned that an ice shelf holding  the Thwaites Glacier could break apart within the next 5 years and result in more ice flowing off the continent into the ocean. If the shelf disintegrates, the glacier’s contribution to sea level rise could eventually increase by as much as 25%.

As satellite technology advances, other scientists have also now observed three glaciers at the South Pole – Pope, Smith and Kohler glaciers are losing ice faster than ever documented, with clarity and completeness never achieved before.

Current warming rate could trigger an abrupt jump in the loss of Antarctic ice sheet after around 2060 & cause multi-metre sea level rise…

…2-5m “cannot be ruled out” by 2100 &2150

This is worrying as emerging research points to grim prospects of the Antarctic ice sheet. If the world continues to warm at its current rate to about 3°C, we could see an abrupt jump in the loss of Antarctic ice sheet after around 2060 leading to multi-metre sea level rise sooner than we think. This is also why for the first time the IPCC AR6 warned in its Summary for Policymakers that 2m of sea level rise by 2100 and 5m by 2150 “cannot be ruled out due to deep uncertainty in ice sheet processes”.

To avoid this catastrophic disaster, we must step up our efforts in decarbonisation as the current emission levels of methane and CO2 do not look promising as they seem.

4. Atmospheric methane is growing “dangerously fast” – potentially a new feedback loop for methane

Methane is a potent greenhouse gas about 28 times more powerful than CO2 at warming the earth. It was responsible for around 30% of warming since pre-industrial period. Yet it was not until last year a global pledge to slash methane emission was announced at the COP26 to increase the hope to limit global warming to 1.5°C.

However, scientists have warned that atmospheric methane is growing “dangerously fast” with global concentrations soaring over 1,900 parts per billion in 2021, nearly triple the pre-industrial period. Methane levels have increased sharply since 2007 yet the reasoning behind remains unclear. Scientists believe this “mysterious” uptick is biological in origin such as from natural wetlands, livestock and agriculture, rather than having been released from below Earth’s surface during the extraction of fossil fuels.

The “mysterious” uptick in atmospheric methane could bring a new methane feedback loop as hotter temperature leads to more methane from wetlands

This is worrying because if the increase of methane comes from wetlands, it could mean we are in a new methane feedback loop. This is where warming of temperature leads to more methane from wetlands, potentially via mechanisms such as increasing the productivity of tropical wetlands, and then that extra methane further warms the planet, leading to more methane.

However, humans are not completely free of blame as human sources such as livestock, agricultural waste, landfill and fossil fuels account for 62% of all methane emissions from 2007 to 2016. Therefore, we must cut all sources of methane emissions as it is probably the strongest action to slow the global heating in the near term.

5. CO2 emissions dip during COVID is only a blip – they are rebounding strongly & rising across the G20

Global CO2 emissions dropped by 7% in 2020 due to the COVID-19 shutdowns, which as it turns out is just a blip in the upward trend of the GHG emissions. The Climate Transparency Report says that CO2 would go up by 4% across the G20 group in 2021, which responsible for 75% of global GHG emissions.

We need to cut global emissions by 7% every year from 2020 levels yet it’s increasing in 2021…

This means that we will need to deliver deeper and faster emission cuts in net zero pledges to meet the 1.5°C Paris target. To stay on track to hit this target, we will need to cut global emissions by over 7% every year at 2020 levels for the next decade. We have less than a decade to do this now. The G20, therefore, has an important leadership role to play by committing to emissions reduction targets and implementing policies that align with 1.5°C pathway.

Sadly, other research found that the carbon footprint gap between the rich and poor is expanding. The world’s richest 10% were responsible for 49% of emissions against 7% produced by the poorest half of the world’s population. Clearly reducing the carbon footprint of the richest may be the fastest way to net zero. If we don’t, the poorest ones will suffer most by the consequences of our changing world which they bear no responsibility.

The world’s richest 10% contributed nearly half of emissions against 7% produced by the poorest 50%…

…clearly reducing the carbon footprint of the richest may be the fastest way to net zero

Ice is vanishing & seas are certain to rise…

These trends only surfaced in the last couple of months and each is worrying but together are sounding major alarm bells. Losing polar ice and rising sea temperatures could kick start a climate domino effect from rising sea level to even shutting down the Atlantic Meridional Overturning Circulation that would severely disrupt global weather patterns. Time is ticking and it’s only a matter of time until low-lying coastal cities are submerged by rising seas unless we fast-track decarbonisation and step-up adaptation.

Further Reading

  • Where Are We On Ice Tipping Points Post COP26? – If we are not careful, we could change weather as we know it – what are these tipping points? How high will seas rise? What will happen to mountain glaciers? See our review of the report State of Cryosphere 2021 for answers
  • It’s Time To Prioritise Sea Level Rise – CWR’s Debra Tan says it’s time to be FOMO about our rising seas. From emission accelerants to accelerated impacts she runs through three reasons to rethink our attitudes towards sea level rise – it’s a big deal, sea level rise is worse than you think. This time, even she’s depressed
  • 3 Ways To Deal With The Deep Uncertainty Of Sea Level Rise – SLR uncertainty is here to stay but it can be minimised as discussed at SIWW 2021. CWR’s Ronald Leung & Dawn McGregor share what the climate & planning experts advised
  • Existential Coastal Threats: 8 Things You Must Know – Rapid SLR will happen sooner than we think, yet we are still driving investments to vulnerable locations. CWR’s Debra Tan shares 8 things you need to know about the existential threat from SLR – from glaciers in the mountains to ice sheets in our poles, permafrost + more
  • Sea Level Rise – What The Science Tells Us – What’s the latest on sea level rise projections? HKU’s Dr. Nicole Khan shares key findings from her survey of 100+ sea level experts, as well as talks risks to Hong Kong and what we should take away from COVID-19
  • Future SLR Projections & Biggest Worries – In this follow up interview, HKU’s Dr. Nicole Khan shares her biggest concerns on how future SLR projections are rising higher & faster than thought & shares the best approach for building realistic scenarios

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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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