Prof Wong Poh Poh's comments on PM's speech on climate change and rising seas

Prof Wong Poh Poh had asked me to share on wildsingapore, his thoughts about PM Lee Hsien Loong's National Day Rally speech on climate change and rising sea levels.

click on image for larger view

Here are Prof Wong's comments without any changes. I absolutely agree with his points 4-6, and learned so much from his other points.

Climate change in the 2019 Draft Master Plan

Under "Adapting to Climate Change", the Plan projects that "by the year 2100, Singapore’s temperature will rise by 1.4°C to 4.6°C and sea levels could rise by up to 1m. The intensity and frequency of heavy rainfall events are also likely to increase while conversely, dry seasons could become even drier."

Glad to see the role of greenery in reducing urban heat is supported. Hopefully, ecosystems can be more fully considered in mitigating flood risks and rising seas.

Singapore's Climate Action Plan and our shores

The Climate Action Plan for Singapore was unveiled yesterday. Great to know that last year's mass fish death is highlighted among the key warning signs of climate impacts to Singapore!

My comments on biodiversity and marine aspects are below. What do you think of the Plan? Please share your thoughts in the comments.

Floods in Singapore and rising seas

Singapore's "overwhelmed" drainage systems are to be upgraded to "bolster the island’s defences against flash floods" and upgrades will be "stepped up". This follows the recent flash floods as the monsoon season starts in Singapore.

From Minister Balakrishnan's facebook page post

Environment and Water Resources Minister Vivian Balakrishnan has asked PUB to speed up ongoing work on 170 projects, and to start work on 36 new projects within 12 months.

Purple rain and Sungei Pandan Kecil

'Purple' rain hits the built up part of Singapore and there's massive flooding, roads not passable to ordinary cars, traffic jams, trees falling.

Rain Areas Animation from the NEA website

Within hours, Minister Vivian Balakrishnan posts on facebook: "flooding at AYE will require expansion of the Sungai Pandan Kechil which drains south to the sea and is subject to tidal influence."

Protecting from rising seas: a role for natural shores?

For the first time, Singapore has started looking at coastal works specifically to protect from rising seas. Hopefully, this will also be an opportunity to incorporate natural regeneration in artificial protective structures. As well as the protection of existing natural shores as a continual source of marine life ‘babies’ and plant seeds and seedlings.

Mangroves settling naturally on an artificial seawall at Pulau Hantu.

The Building and Construction Authority (BCA), which is in charge of protecting the island nation's coasts, last month called a tender for a coastal adaptation study - the most extensive one done here yet - to come up with a framework to keep low-lying areas safe.

What shores will Singapore lose in 7-million population plan?

How will Singapore's shores be affected by plans for a 7-million population by 2030? The landuse plan by the Ministry of National Development released today shows some of the shores that may be lost.

These include Chek Jawa, Pulau Sekudu, Changi shores, Mandai mangroves and probably Pasir Ris mangroves too, if land reclamation (in yellow) plans goes ahead.

Sea level rise and Singapore's response

For the first time, it was mentioned that Singapore "will need to raise minimum levels for land reclamation by at least 1m to create an adequate buffer against a potential rise in sea level". This, according to the Ministry of Environment and Water Resources (MEWR).

In Mar 2010, a Singapore study revealed that sea levels could rise by between 24 and 65cm by 2100. At that time, the Ministry said existing regulations were sufficient. These included a requirement since the early 1990's for reclaimed land to be built at a height of 125cm above the highest measured tidal level, as a buffer against rising sea levels.

Why are rising sea levels a concern for Singapore?

An engineer's view of reclamation and dredging

What actually goes on during the dredging and reclamation that are happening on many of our shores?

Massive dredging near Cyrene Reef, July 2011

I came across some articles in Port Strategy with engineering details on such coastal works. Including how environmental concerns are met.

SiReNT, coastal erosion and mangroves

SiReNT (Singapore Satellite Positioning Reference Network) is an ultra-precise satellite navigation network that can be used, among others, to study coastal erosion and natural habitats.
Pulau Semakau will host the sixth and latest point on the system. It will also be used to"study the environment around the southern tip of Singapore, measuring coastal erosion, natural habitats and tidal activity in the area."

Is this a big deal?

Sea level rise in Singapore: what effects?

By 2100, sea levels could rise by between 24 and 65cm, according to a study by Tropical Marine Science Institute at the National University of Singapore (NUS).
What areas in Singapore could be affected by sea level rise?
From Sea Level Rise Explorer, the low lying areas in Singapore include Changi Airport (above).

Rising seas and Singapore, on Blog Action Day

Pancake flat and surrounded by the sea: is how Singapore has been described.

Singapore from the sea.

Blog Action Day 2009 on 15 Oct has the theme of climate change. Among the many effects of climate change that Singapore faces is a long, slow submersion as sea levels creep up.

This video clip shared on YouTube was taken in January this year at East Coast Park.

How sea level changes affect mammals in the Malay Peninsula

A new explanation has been offered for an apparently abrupt switch in the kinds in of mammals found along the Malay Peninsula in southeast Asia – from mainland species to island species – in the absence of any geographical barrier.Sixteen thousand years ago surrounding seas were 110 meters lower than today. (Credit: Maps drawn by Clara Simpson, Field Museum, University of Chicago.)

The study suggests more than 58 rapid sea level rises in the last 5 million years could account for the shift by crowding out species, particularly at the narrowest part of the peninsula called the Isthmus of Kra.

“We studied mammals from China down to Singapore,” said David Woodruff. But they found no evidence for a sharp transition between types of mammals at Kra or anywhere else along the peninsula. Instead, they saw a gap. “We found an area about 600 kilometers long where there are 30 percent fewer species than there should be.”

A long time ago, I was helping out with a study of our Dog-faced watersnakes (Cerberus rynchops) conducted by the Field Museum of the US. Their work on such humble creatures also threw light on sea level changes in our region. There's much we can learn from our shores, because we are part of a grand spectrum of biodiversity, very much affected by the seas.

New Explanation For A Puzzling Biological Divide Along The Malay Peninsula
ScienceDaily 5 Mar 09;

Ecologists at the University of California, San Diego, offer a new explanation for an apparently abrupt switch in the kinds in of mammals found along the Malay Peninsula in southeast Asia – from mainland species to island species – in the absence of any geographical barrier.

An ancient seaway between the Gulf of Thailand and the Andaman Sea was once thought have split the peninsula in two, allowing separated populations of animals to diverge. But a recent revision of the history of sea levels reveals that the ocean hasn’t cut through the peninsula in the past 40 million years. Current species of mammals are much younger than that.

Instead, David Woodruff, professor of biology at UC San Diego and former graduate student Leslie Turner, now at the Max Planck Institute for Evolutionary Biology in Ploen, Germany, say that more than 58 rapid sea level rises in the last 5 million years could account for the shift by crowding out species, particularly at the narrowest part of the peninsula called the Isthmus of Kra. The Journal of Biogeography posted their findings online February 25.

For most of the past few million years, the shallow ocean shelf surrounding the peninsula and islands of Malaysia and Indonesia has been exposed, creating a land area about the size of Europe. That habitat shrank dramatically each time sea levels rose.

“The ocean is coming from both sides repeatedly to squeeze things,” Woodruff said. “If you have the ocean edge coming back and forth more than 50 times around this little narrow area, you’ll compress the fauna and cause species to go extinct locally.”

By consulting published reports, Woodruff and Turner mapped the ranges of 325 species of mammals found in the region. “We studied mammals from China down to Singapore,” Woodruff said. But they found no evidence for a sharp transition between types of mammals at Kra or anywhere else along the peninsula.

Instead, they saw a gap. “We found an area about 600 kilometers long where there are 30 percent fewer species than there should be,” Woodruff said. Although 128 mainland Asian species stopped before the southern tip of the peninsula and 121 island species were found only in the south, 35 widely distributed species were found above and below the isthmus, but were missing from that narrowest part.

More links

• Pleistocene sea level maps for Southeast Asia on the Field Museum website.
• Biogeographical implications of mitochondrial DNA variation in the Bockadam snake (Cerberus rynchops, Serpentes : Homalopsinae) in Southeast Asia, Karns D. R., O'Bannon A., Voris H. K., Weigt L. A.
• Aquatic snake project at Pasir Ris Singapore by the Field Museum
• Snake hunters on the Raffles Museum of Biodiversity Research
  

"No clear rise in sea level in Singapore in last 12 years"

"Our data, based on a measurement of maximum tide levels, show no clear rise in sea level in Singapore over the last 12 years", said Associate Professor Ho Juay Choy, principle fellow at the Energy Studies Institute (ESI) at the National University of Singapore (NUS).

Super high tide at Chek Jawa boardwalk in Oct 08

Previous reports say that a metre-high rise in sea level is enough for several areas around the island to be submerged. 'The increased probability of flooding and coastal erosion as well as saltwater intrusion into fresh water reservoirs are some of the possible consequences,' said Associate Professor Matthias Roth of the department of geography at NUS.

While Singapore may not be drowning yet, it is getting hotter here and at a faster rate over the last two decades.

Last year's average temperature of 27.5 deg C, was 0.6 deg C higher than the average temperature over the last 50 years of 26.9 deg C, said the National Environment Agency (NEA).

From 1951 to 1979, average temperature levels were below this long-term average. But since 1983, they have been on the rise, hovering between 0.1 deg C and 0.6 deg C above the long-term mean.

The NEA said it was difficult to determine how much of the upward trend was due to global warming and how much to Singapore's rapid development and urbanisation over the past 30 years.

'But the trend is consistent with rising global temperature levels,' a spokesman added.

These findings will be part of a country report for Singapore on the Regional Review of the Economics of Climate Change for South-east Asia. The report is being prepared for the Asian Development Bank (ADB).

Singapore's carbon intensity - which measures the ratio of carbon emissions to economic activity - has improved from 0.28 kt/$m (kilotonnes/million GDP) in 1990 to 0.20 kt/$m in 2006.

'This is a direct result of Singapore's efforts to switch from fuel oil to natural gas for power generation and initiatives aimed at improving energy efficiency in various sectors of the economy,' said Prof Ho.

According to the International Energy Agency (IEA), Singapore's carbon intensity levels are below the world average.

From Singapore is hotter than before Amresh Gunasingham, Straits Times 3 Jan 09;

More links

• Report on climate change effects on Singapore expected in 2009 Julia Ng, Channel NewsAsia 31 Dec 08;
• Singapore at 7m sea level rise
• Rising sea levels discussed in Singapore Parliament
• Singapore and rising sea levels

Faster, cheaper land reclamation in Singapore

By 2030, another 50 sq km is set to be added - so Singapore will have expanded by a quarter altogether.

An initiative by the Singapore Land Authority (SLA) and Jurong Town Corporation (JTC) will involve scientific analysis of the impact of waves on different stretches of the coastline and reclaimed land. Engineers will then determine the appropriate level of shoreline protection to be put in place for three months until a tenant takes over the land.

The first test case for the new approach is the reclamation that has been done for a mega shipyard in Tuas.

For every kilometre of shoreline of land reclaimed under the new approach for the shipyard, the Government saved five months in construction time and about $11.25 million in costs. The shipyard owner saved nearly three months in construction time and about $4.5 million.

SLA is the gatekeeper for all land reclamation projects in Singapore.

The full article is on the wildsingapore news blog.

Is it safe to move quickly onto reclaimed land?

From Singapore tremors raise fear of building on reclaimed land by Koh Gui Qing, Reuters 9 Mar 07.

"Reclaimed land is made up of sea sand, so buildings will be shaken up more violently during earthquakes as compared to those on non-reclaimed land, which is solid and will not be liquefied by the shake," said Fan Sau Cheong, an engineering professor at Singapore's Nanyang Technological University. He told Reuters that buildings on reclaimed land may shake two to three times more than those on natural land during earthquakes because sand in reclaimed land slides like liquid when saturated with water, in a process called liquefaction.

From Is Singapore quake-proof? Lin Yanqin Today Online 20 Jan 05

"Singapore stands on extensive soft marine clays and sands. You have massive cargo ports and harbours on reclaimed land," Prof Rice said. "I think you should put in place a set of studies to realistically assess the plausible size of earthquakes and the detailed response of structures in Singapore."

As Singapore's history does not go back long enough to document earthquakes which may have occurred centuries ago, it should not think it is immune to the threat of a major earthquake off Sumatra's western coast, Prof Rice said.

He likened Singapore to Mexico City, which was devastated by an earthquake in 1985 because it was built on the bed of an old lake.

What about sea level rise?

From Vulnerable to rising seas, Singapore envisions a giant seawall By Wayne Arnold, International Herald Tribune 29 Aug 07

Singapore got a preview of just what havoc rising sea levels could cause back in 1974 when a rare astronomical event caused the tides to rise 3.9 meters, more than double the usual level.

"It eroded the coast very badly," said Wong Poh Poh, an associate professor specializing in beach geography at the National University of Singapore, who studied the event.

Areas along the Singapore River were inundated, as were parts of the airport and a coastal public park built on reclaimed land. Wong later discovered that during such periods of elevated sea levels, the variations between high and low tide are accentuated, putting the country's reservoirs, many of which lie adjacent to the coast, at risk.

More background on reclamation in Singapore

From Singapore Finds it Hard to Expand Without Sand by Koh Gui Qing PlanetArk website, 12 Apr 05

Under a Concept Plan 2001, Singapore wants to add another 99 sq km (38 sq miles) over the next five decades. Civil engineers say that would be costly and require massive amounts of sand.

When reclamantion works began in earnest in the 1960s, the depth off Singapore's shore was about 5 metres (16 ft). That has sunk to about 20 metres (65 ft), requiring four times as much sand -- and four times more money -- to fill every square metre.

For a sense of scale, and cost, take Singapore's Changi Airport. Its 20 sq km (7.7 sq mile) of reclaimed land required 272 million cubic metres (9.6 billion cubic ft) of sand, said a civil engineering professor at a local university. The sand alone would have cost at least S$1.9 billion.

For now, Singapore may refocus on its own undeveloped land. About 41 percent of the island is either undeveloped or taken up by reservoirs, cemeteries, farms, army camps and nature reserves.

More links to land reclamation and shore protection in Singapore

• Erosion on Singapore's shores on the wild shores of singapore blog.
• Land Reclamation in Singapore a one-page outline of key issues on ThinkQuest
• Offshore Land Reclamation Methodology (PDF) lots of details of exactly how land reclamation is carried out in Singapore from "Field measurements and back-analysis of marine clay geotechnical characteristics under reclamation fills" by Arulrajah, Atputharajah, Curtin University of Technology, Department of Civil Engineering, 2005.

Rising seas: time to buy a new homeland?

The Maldive is already looking into buying a new homeland.

Most parts of the Maldives are just 1.5m above water. Even a "small rise" in sea levels would inundate large parts of the archipelago. The UN forecasts that the seas are likely to rise by up to 59cm by 2100, due to global warming.

Maldives newly elected president Mohamed "Anni" Nasheed, said "We can do nothing to stop climate change on our own and so we have to buy land elsewhere. It's an insurance policy for the worst possible outcome. After all, the Israelis [began by buying] land in Palestine,"

He said Sri Lanka and India were targets because they had similar cultures, cuisines and climates. Australia was also being considered because of the amount of unoccupied land available. "We do not want to leave the Maldives, but we also do not want to be climate refugees living in tents for decades."

In Five nations under threat from climate change on the Short Sharp Science blog, besides the Maldives, the other four countries include Tuvalu which could be gone by the middle of this century; Kiribati; Carteret Islands of Papua New Guinea -- where a trial relocation last year led to relocated citizens being used as labourers in coconut plantations on Bougainville; Bangladesh's Bhola Island -- in 1995, half a million of its inhabitants were forced to move in when half their island was permanently flooded.

What about Singapore?

In the latest parlimentary discussion on the issue:

Minister Yaacob Ibrahim answered both MPs by first stating that the United Nation's Intergovernmental Panel on Climate Change (IPCC) projected last year that climate change could lead to sea level rises of between 18cm and 59cm by the year 2100.

This does not factor in the rapid melting of Greenland or Antarctic ice sheets, as the understanding of these effects is too limited.

Since 1991, all new reclamation projects have to be built to a level 125cm above the highest recorded tide level.

This is 66cm more than the IPCC's projected highest sea level rise of 59cm by the end of the 21stcentury in the worst-case scenario.

Here's some older posts on the issue.

• Full text of parliamentary discussion on rising sea levels and impact on Singapore
• Singapore at 7 metre sea level rise
• Singapore and rising sea levels discussed in parliament
• Singapore and rising sea levels What do rising sea levels mean for Singapore?

"Prepare for one metre sea level rise this century"

This is higher than the most pessimistic projection by the UN climate panel. And is a finding by the Potsdam Institute for Climate Impact Research (PIK), which advises the German government on environmental policy. More in Sea levels could rise one metre by 2100: German institute.

PIK is part of the group of scientists who raised the idea of Tipping Elements In Earth's Climate System in Feb 08. Which noted that "Society may be lulled into a false sense of security by smooth projections of global change."

However, in some regions, man-made causes affecting the climate system could kick start abrupt and potentially irreversible changes. For these sub-systems of the Earth system the researchers introduce the term "tipping element".

They shortlisted nine tipping elements relevant to current policy-making. All of them could be tipped within the next 100 years.

• Melting of Arctic sea-ice (approx 10 years)
• Decay of the Greenland ice sheet (more than 300 years)
• Collapse of the West Antarctic ice sheet (more than 300 years)
• Collapse of the Atlantic thermohaline circulation (approx 100 years)
• Increase in the El Nino Southern Oscillation (approx 100 years)
• Collapse of the Indian summer monsoon (approx 1 year)
• Greening of the Sahara/Sahel and disruption of the West African monsoon (approx 10 years)
• Dieback of the Amazon rainforest (approx 50 years)
• Dieback of the Boreal Forest (approx 50 years)

Full text of parliamentary discussion on rising sea levels and impact on Singapore

Questions on a 140cm sea level rise and building dykes were also raised. These were not mentioned in earlier media reports on the parliamentary discussion.

Rising Sea Levels
(Measures to monitor effects and impact on Singapore)
from Hansard (Singapore Parliament Reports) on the Singapore Parliament website

5. Dr Lam Pin Min asked the Minister for the Environment and Water Resources in view of the rising sea levels due to climate change, what long term measures are contemplated to protect Singapore's coastline and to avoid major catastrophes.

6. Mr Low Thia Khiang asked the Minister for the Environment and Water Resources whether his Ministry has assessed the recent findings that the Greenland ice sheet is melting faster than expected and what impact, if any, would these findings have on Singapore.

7. Mr Low Thia Khiang asked the Minister for the Environment and Water Resources whether the Government is prepared for a possible rise in sea level and, if so, what measures have been planned in response.

Assoc. Prof. Dr Yaacob Ibrahim: Mr Speaker, Sir, with your permission, can I take Question Nos. 5, 6 and 7 together please?

Mr Speaker: Yes.

The Minister for the Environment and Water Resources (Assoc. Prof. Dr Yaacob Ibrahim): Sir, climate change is a global challenge. The direct effects of climate change include shifts in temperature, rainfall patterns, storm surges, and many others. In recent years, many countries have experienced more frequent occurrences of extreme weather events, such as the Hurricane Katrina in the US, Cyclone Nargis in Myanmar and episodes of severe floods in India and China.

The United Nation's Intergovernmental Panel on Climate Change (IPCC) projected in its Fourth Assessment Report, which was released last year, that climate change could result in sea level rises of between 18 cm and 59 cm by the year 2100. This does not factor in the rapid melting of Greenland or Antarctic ice sheets, as the understanding of these effects is too limited to assess their likelihood or provide a best estimate or an upper bound for sea level rise. Scientists are currently working to better understand and project the rate at which the ice sheets may melt, as well as the resulting impacts.

As a relatively low-lying, densely populated island in the tropics, Singapore is vulnerable to climate change effects like sea level rises, which can lead to inland flooding. However, as a result of our environmental and developmental planning in the past, we already have existing measures in place that significantly reduce our exposure to the risks.

Since 1991, all new reclamation projects have to be built to a level 125 cm above the highest recorded tide level. This requirement is 66 cm more than the IPCC's projected highest sea level rise of 59 cm by the end of the 21st century in the worst case scenario. Singapore is as such well prepared for any further increases in sea level arising from climate change within the range of over one metre.

The development of drainage infrastructure in Singapore over the last 30 years has also reduced flood-prone areas from 3,200 ha in the 1970s to 98 ha today. PUB will reduce it to less than 48 ha by 2011 through the development and improvement of drainage infrastructure in Singapore, such as the widening and the deepening of drains and canals. While the objective of this is to reduce the flood-prone areas and alleviate flooding today, the overall enhancement in the drainage system helps to reduce the possibility of upstream flooding when heavy rain coincides with high tide or sea level rise due to climate change. The completion of the Marina Barrage project has also enhanced our flood alleviation capabilities.

However, we cannot be complacent in our efforts. It is important that we continue improving our understanding of the specific effects and impacts of climate change on Singapore. I announced last year that NEA, in consultation with other Government agencies, has commissioned a two-year study to understand the specific implications of climate change in Singapore, based on the IPCC studies. These include sea level and temperature changes, flooding and coastal erosion.

This study into Singapore's vulnerability to climate change is expected to be completed next year. It will help us better understand how Singapore will be affected and what needs to be done to protect Singapore and ensure that we are able to adapt to these impacts. We also continue to monitor closely the developments in scientific understanding of the melting of ice sheets and its impacts. Our study will give us modelling capability to factor in any new scientific findings to assess the localised effects on Singapore. This information will help in reviewing the adequacy of the existing adaptation measures and whether further enhancements are needed.

Ms Irene Ng Phek Hoong (Tampines): Sir, given that Singapore is a low-lying island, can I ask the Minister whether there are further moves to study from the Dutch about building dykes, given that we are very vulnerable to flooding?

Assoc. Prof. Dr Yaacob Ibrahim: Sir, there is an inter-agency task force led by MND to review existing infrastructure adaptation measures as part of the overall Government's response to climate change. This task force will look at measures for Singapore to adapt to the sea-level rise through the protection of foreshore and coastal areas.

But as I have mentioned earlier, our reclaimed land today is well above the highest recorded tide, so this will provide some protection against any sea-level rise due to global warming. But this is based on current information. So the task force, when they review their adaptation measures, will consider the findings from the vulnerability study which I have mentioned earlier. The study is not over yet. Once it is over, we will look at it and see whether we need to enhance existing measures or introduce new ones. At the moment, I think the task force is looking at all options.

Dr Lily Neo (Jalan Besar): Mr Speaker, Sir, may I have two supplementary questions please? May I ask the Minister how does he protect Singapore shores against a rising sea-level of 140 cm, a possible figure, according to one international study, and the same figure I posed to him at last year's COS debate on the same issue.

Secondly, the Minister said last year at the COS debate that they have commissioned a study to better understand the possible long term effects and the impacts of climate change on Singapore. He did say that he will get the preliminary reports after one year and, therefore, may I ask him after one year, what are these preliminary reports?

Assoc. Prof. Dr Yaacob Ibrahim: Sir, we have to go by the best available report, and in this case, the IPCC. So I am not sure where the Member has got the figure of the 140 cm, but we will be most happy to receive that particular report from her and study it.

We have to go by the IPCC because IPCC is a collection of experts across the world looking at various scenarios and the best estimate in the report, as I have mentioned in my reply, is between 18 cm and 59 cm. But having said that, we will continue to study any further scientific reports, including the one that was reported earlier, which is the question filed by Mr Low and Dr Lam, and we will study all these as part of the vulnerability study.

On her second point as to whether we have completed the interim study, the answer is yes. The findings are preliminary in nature because this is a long-term study. It will take us two years as we need to drill down the IPCC report to our context in Singapore which is located near the Straits of Malacca and South China Sea. From what we can understand, the preliminary findings show that the projection for sea-level rise is between 4 cm and 5 cm per century, and the sea level will increase over the global mean projection of 21 cm to 48 cm.

So based on the preliminary finding, our requirement of 125 cm above the highest recorded tide-level is sufficient to deal with the estimates given by the preliminary findings. With that, we are now going into the second phase of the study where we are going even deeper into some other aspects of the effects of climate change on Singapore.

Mr Speaker: Dr Neo, last question.

Dr Lily Neo: Thank you, Mr Speaker. I was asked on where I got my report. I just want to say that this report came from Global Research on Oceans Warming and Rising by International Federation of Environmental Journalists and is done by using data from US National Aeronautics and Space Administration or NASA by a German professor.

This is possibly the report referred to by Dr Lily Neo:

Oceans Warming and Rising
World Business Council for Sustainable Development website

IPS, 21 December 2006 - Ocean levels will rise faster than expected if greenhouse gas emissions continue to rise, a leading German researcher warns.

Using data from the U.S. National Aeronautics and Space Administration (NASA), Stefan Rahmstorf, professor of physics of the oceans at the University of Potsdam near Berlin estimates that sea level could rise 140 cm by 2100.

Rahmstorf, member of the German Advisory Council on Global Change, is considered a leading European researcher on global warming and its effect on oceans.

"The semi-empirical model we used to process NASA data showed a proportional constant sea level rise of 3.4 mm per year per degree Celsius," Rahmstorf told IPS. "Then we applied this constant proportionality to future earth surface warming scenarios of the Intergovernmental Panel on Climate Change (IPPC), and came to estimate that by the year 2100, sea level could rise between 50 and 140 cm above the level measured in 1990."

Through the 20th century, global warming led to an average 20cm rise in sea level. But most computer models of climate change used at present significantly underestimate sea level rise, Rahmstorf said. "Future projections of sea level based on these climate models are therefore unreliable."

Currently, sea level is rising at three cm per decade, faster than projected in the scenarios of the IPCC Third Assessment Report, Rahmstorf added.

The IPCC, an intergovernmental team of scientists carrying out a wide range of research related to climate change, was established in 1988 by the World Meteorological Organisation and the United Nations Environmental Programme. The IPCC aims to assess scientific, technical and socio-economic information relevant for understanding of climate change, its potential impact, and options for adaptation and mitigation.

Scientific research has found that industrial activities have produced greenhouse gas emissions considerably higher than levels observed before the industrial revolution.

Concentration of carbon dioxide (CO2), the most potent of greenhouse gases, has risen from about 280 parts per million (ppm) in the atmosphere in the year 1750 to about 380 ppm today.

This rise is primarily due to the burning of fossil fuels, and to a lesser extent, deforestation. Scientists estimate that if the present emissions trend continues, the atmosphere could heat up by about five 5 degrees Celsius by 2100.

Studies by the Potsdam Institute for Climate Impact Research suggest that this would roughly be the temperature difference between an ice age and a warm stage. But while the rise of average temperatures by some five degrees between the last great ice age and today took 5,000 years, the new global warming would need only 100 years.

Rahmstorf acknowledged that forecasts of global warming and its effects on sea levels continue to be marked by uncertainty. "The fact that we get such different estimates using different methods shows how uncertain our sea level forecasts still are," Rahmstorf told IPS.

A major reason for the uncertainty is the behaviour of the large ice sheets in Greenland and Antarctica.

A likely consequence of a massive melting of the ice masses on the North Pole could be the breakdown of the North Atlantic Current (NAC). The NAC is the northern extension of the Gulf Stream, and constitutes a warm water current flowing between Britain and Iceland. This has considerable impact in moderating the North European and Scandinavian climate.

"One critical factor for the continuation of this current is the amount of fresh water that enters the Northern Atlantic region in the future," Rahmstorf said. "This will depend in large part on the speed at which Greenland's ice sheet melts."

Rahmstorf, who earlier this year co-authored a research paper titled 'The Future Oceans -- Warming Up, Rising High, Turning Sour' said that reliable prediction on the risk of a total stoppage of deepwater formation in the Northern Atlantic is not possible given present knowledge.

But he pointed out that experts have evaluated that risk at more than 50 percent if global warming is between three and five degrees.

Rahmstorf said greenhouse gases emissions are also increasing the acidity of oceans. "In the atmosphere carbon dioxide does not react with other gases, but in the ocean it dissolves, contributing to the acidification of seawater," Rahmstorf said. This acidity is a serious threat to marine biodiversity.

"There is a good chance to avoid such dangerous climate change if global warming caused by human activities is limited to two degrees in the coming decades," Rahmstorf said.

(*This story is part of a series of features on sustainable development by IPS - Inter Press Service and IFEJ - International Federation of Environmental Journalists.)

Singapore at 7 metre sea level rise

Will anything be left of our tiny little island? Any bits sticking out? For practical Singaporeans, this information might be useful in guiding property purchase decisions...

Peizee shares a map based on a study of the impact of a 7 metre sea level rise, and some thoughts about the issue on her blooooooooooo blog.

Here's a map from the Sea Level Rise Explorer
More maps

• Flood maps simulates submergence at various levels of sea rise from +1m to +14m. Here is the map for Singapore at +7m
• Hazard sites to consider on the spatial world blog with links to other sites with maps of flooding, fires, terrorism, hurricanes and other unpleasant things that could happen.

See also earlier post about Singapore and rising sea levels discussed in Parliament.

Singapore and rising sea levels discussed in parliament

Parliament discussed rising seas on 15 Sep 08. There was a brief report of this in the Straits Times, and a much fuller report in the New Paper online today.

Seems Singapore is OK so long as we don't "factor in the rapid melting of Greenland or Antarctic ice sheets". And why don't we factor this in? "The understanding of these effects is too limited."

A study by the Scripps Institution of Oceanography released on 15 Sep 08 found that the planet is "already committed to 2.4 degree C rise from climate change". It also pointed out that "the Intergovernmental Panel on Climate Change (IPCC) has warned that a rise in global temperature by 1 to 3°C will lead to catastrophic consequences, including “widespread deglaciation of the Greenland Ice Sheet".

How much will sea levels rise if Greenland Ice Sheet melts? From the above study, "long-term exposure (thousands of years) of the Greenland Ice Sheet to a minimum warming between 1.9–4.6°C will lead to a complete melt of Greenland. Such a melt would raise sea levels by seven meters".

Sea levels may rise: But Singapore's okay
by Teh Jen Lee in The New Paper 17 Sep 08
full article also on the wildsingapore news blog

Some extracts ...

Minister Yaacob Ibrahim answered both MPs by first stating that the United Nation's Intergovernmental Panel on Climate Change (IPCC) projected last year that climate change could lead to sea level rises of between 18cm and 59cm by the year 2100.

This does not factor in the rapid melting of Greenland or Antarctic ice sheets, as the understanding of these effects is too limited.

Since 1991, all new reclamation projects have to be built to a level 125cm above the highest recorded tide level.

This is 66cm more than the IPCC's projected highest sea level rise of 59cm by the end of the 21stcentury in the worst-case scenario.

Singapore's development of drainage infrastructure over the last 30 years has reduced flood-prone areas from 3,200 ha in the '70s to 98ha today.

PUB will reduce it to less than 48 ha by 2011 through the development and improvement of drainage infrastructure, such as the widening and deepening of drains and canals.

While the objective of this is to reduce the flood-prone areas and alleviate flooding today, a better drainage system helps to reduce the possibility of upstream flooding when heavy rain coincides with high tide or sea level rise.

In addition, the National Environment Agency, in consultation with other government agencies, commissioned a two-year study last year to understand the specific implications of climate change in Singapore, based on the IPCC studies.

These include sea level and temperature changes, flooding and coastal erosion. The study is expected to be completed next year.

Earth already committed to 2.4 degree C rise from climate change
Jeremy Hance, mongabay.com 15 Sep 08;
full article also on the wildsingapore news blog

Some extracts ...

As of 2005 the Earth was already committed to rise of global mean temperatures by 2.4°C (4.3°F), concludes a new study published in the journal Proceedings of the National Academy of Sciences (PNAS).

The researchers estimate the long-term exposure (thousands of years) of the Greenland Ice Sheet to a minimum warming between 1.9–4.6°C will lead to a complete melt of Greenland. Such a melt would raise sea levels by seven meters (23 feet).

Air pollution masking climate change

Ramanathan and Feng also explore a question often raised by skeptics: "Why hasn't the planet yet felt the full force of climate change?" So far, the planet has experienced a mean warming of 0.76°C since the late 1800s.

The scientists conclude that a variety of factors are masking the full effect of climate change; one of the most significant of which is air pollution. Some types of air pollution send aerosols that reflect light like a mirror, brightening the planet and thereby cooling it. The pollutants ability to mask rising temperatures has been estimated at 47 percent. However, as nations clean up their skies, the masking effects of such pollutants disappear causing the Earth to undergo sudden warming. The researchers state that this relationship between dwindling air pollutants and higher temperatures can already be seen in Europe.

More links
Here's some past media articles about this issue

• Rising sea levels: Stakes high for port cities
  Michael Richardson, Straits Times 15 Sep 08
• Sea levels rising? Plant mangroves
  Experts say they are a cheap and effective way to protect low areas
  Shobana Kesava, Straits Times 26 Jul 08
• Island Nations Plan for Rising Seas, Mass Migration
  Singapore rep "We are reclaiming land and expanding"
  Ajay Makan, PlanetArk 15 Nov 07
  
• MM Lee finds climate change a 'woeful' topic
  Governments still lack the will to stop environmental degradation, he says
  Lynn Lee Straits Times 26 Sep 07
  
• Vulnerable to rising seas, Singapore envisions a giant seawall
  Wayne Arnold International Herald Tribune 29 Aug 07
  
• Build dykes to protect against rising sea levels: experts
  Channel NewsAsia 9 May 07
  
• Government preparing for possibility of rising sea levels
  Zakir Hussain The Straits Times 23 Apr 07

Want to say something about this?Sustainable Singapore is an effort to gather public feedback by end October about what Singapore and Singaporeans can do about climate change. More about this in an earlier post.