Unabated greenhouse gas emissions could lead to sea level rise twice as high as we had anticipated, according to a recent study published in Nature.
By the end of this century, scientists predict that sea levels could rise by over 2 meters on average. Note that this is a global average, meaning that some areas could see much higher local rises in sea level. For Small Island Developing States, this could mean the end of their existence altogether. The research has been welcomed by the scientific community, who had already raised reservations with regards to what was called “very conservative” estimates of sea level rise caused by a changing climate.
So what has changed, how could we suddenly double sea level rise? The answer lies in complex processes involved in the melting of ice in Antarctica. Previous estimates had failed to take into account accelerated melting caused by disintegrating ice sheets. In fact, scientists had only been able to consider the melting ice shelves due to increased air and water temperatures, and had ignored the impact of surface melt-water and rainfall which can help fracture large chunks of ice.
Climate change adaptation has been hailed as the ultimate recourse to prevent negative impacts of sea level rise. For instance, in a number of coastal regions, ecosystem-based adaptation helped by mangroves has been underway for some years already. Mangroves play a significant role in protecting coastal regions from intense storms including typhoons, expected to increase in frequency with climate change. Combined with sea level rise, such storm could be catastrophic, especially in densely populated areas.
In previous adaptation planning, the unique property of mangroves to “grow soil” had been counted on to mitigate the impacts of rising sea levels. The rate of growth of mangroves was very much in line with previous climate change projections, yet this new data would suggest that these fragile ecosystems would no longer be able to keep up with the increased rate of sea level rise. Hence, millions of the most vulnerable coastal communities will likely have to rethink their adaptation strategies, a very costly endeavour.
So what is the silver lining? If we achieve the targets set in the 2015 Paris Agreement, sea levels will continue to rise, but never to the rate which would occur if Antarctica’s melting was to start accelerating. Coastal communities will still need to adapt, but costs will be reduced and lives will be saved.
Lying on the floodplains of the mighty Ganges, Brahmaputra and Meghna rivers Bangladesh is a rich, fertile land. These giant river systems meet in the centre of the country and flow together into the Bay of Bengal which, at over 1600km wide, is the largest delta in the world.
Rising Sea Level
Bangladesh is often cited as one of the countries that will be most negatively affected by rising sea levels from human induced climate change. Two thirds of the country lies less than 5m above of sea level. With vast regions to the south much less than a 1m above sea level. The Intergovernmental Panel on Climate Change (IPCC) claims that just 1m rise in sea level could directly expose nearly 14 million people and result in potentially 17% land loss in southern Bangladesh.
Most of the country receives on average more than 2.5m of rainfall a year, 80% of which falls in about 4 months during the peak monsoon season, resulting in large annual floods. The flood waters bring nutrient rich clays and silts from the high Himalayas and deposit them on the river floodplains. These rich soils produce bountiful harvests of rice and other crops. Unsurprisingly, farming is the most common profession.
However floods, once welcomed by farmers and their families are now harbingers of disaster. Human induced climate change has resulted in more erratic monsoon weather patterns with often larger than normal volumes of water being delivered in shorter time intervals. The resulting floods have had devastating effects on the Bangladeshi people. In 2012 three large floods hit the country in swift succession between the months of July and September directly affecting more than 5 million people. These are now a common annual occurrence.
Bangladesh is also subject to annual tropical cyclones, storm surges and tornadoes. Some of the worst natural disasters in recorded history were results of cyclonic storms in the Bengal region. Among them, the 1970 Bhola cyclone which claimed over 500,000lives! Worryingly new research into the impacts of climate change has shown that large cyclonic storms will become a more common occurrence in the years and decades to come.
The foothills of the great Himalayan mountain belt has historically been the location of many large earthquakes. Earthquakes in the continent tend to be more infrequent compared to regions such as Japan and California. However this makes them more unpredictable and often unexpected. But when one does occur it can result in significant ground shaking. The 1897 magnitude 8.1 and 1950 magnitude8.7 Assam earthquakes were two of the biggest to hit the region in recent times. The current building stock in Bangladesh is poorly built and most are not built to withstand ground shaking in an earthquake. The collapse of poorly built buildings is the greatest hazard during an earthquake.
So what can we as earth scientists do?
Bangladesh has a population of over 160 million and among the highest population density of any country in the world. With the majority of the country built on river floodplains combined with widespread corruption and ignorance a large earthquake could quite possibly result in the greatest natural calamity to have ever hit the country!
Bangladesh needs to increase its resilience if its people are to survive the multitude of natural hazards they face. Earth scientists are well placed to understand the risks involved from these hazards and can play a key role in all aspects of building a resilient infrastructure.
Climate science research is ongoing and needs to continue to better understand the affect human induced climate is having and will have on the annual monsoon. This knowledge needs to be translated into rainfall variation and flooding potentials and communicated with the people who need this information. The socio-economic issues of a rising sea level needs to be addressed and plans put in place to allow big cities to efficiently absorb and cater for migrants moving away from hazard prone coastal regions. Hydro-geologists and geochemists are helping to find sustainable clean, arsenic free water sources for drinking and farming. Seismologists and earthquake scientists are working to better understand the seismic risk in the Himalayan foothills; produce more accurate hazard maps and importantly identify the active faults within the region.
These are to name but a few of the ways earth scientists can get involved. I believe it is our moral duty to translate the practical aspects of our science into real benefits for people.
A historic agreement to tackle climate change and pave the way towards a low carbon, greener and cleaner future has been adopted by 195 nations in Paris.
This was a truly monumental political achievement that was only possible because of the deep urge felt unanimously by all member nations to act on one of the greatest challenges humanity has ever faced; that the climate is changing with disastrous consequences for people all over the world.
The Paris Agreement’s main aim is to limit global warming to well below 2 degrees Celsius by the end of the century and to drive efforts to limit temperature increase to 1.5 degrees.
The 1.5 degree Celsius limit is a significantly safer defence line against the worst impacts of a changing climate.
To reach these ambitious goals will require collaboration in a global scale, with richer nations providing much of the financial and technological means to implement low carbon, green initiatives throughout the world.
French President Francois Hollande told the assembled delegates: “You’ve done it, reached an ambitious agreement, a binding agreement, a universal agreement. Never will I be able to express more gratitude to a conference. You can be proud to stand before your children and grandchildren.”
Over the next few weeks I will be posting about the key implications of this agreement.
A declaration by Islamic scholars calls on global leaders to reduce greenhouse gas emissions and suggests that Muslims have a religious duty to tackle climate change.
The Islamic Declaration on Global Climate Change, drawn up by a group of academics, Muslim scholars and international environment policy experts, was announced recently at a symposium on Islam and climate change in Istanbul. It calls on the 1.6 billion Muslims around the world to phase out our reliance on fossil fuels and switch instead to clean energy from renewable sources.
The statements reiterates the now well documented rise in global average surface temperatures since the industrial revolution and attributes this increase to excessive burning of fossil fuels.
It states that: “This current rate of climate change cannot be sustained, and the Earth’s fine equilibrium (mīzān) may soon be lost.”
The declaration laments the slow progress of international climate-change negotiations: “It is alarming that in spite of all the warnings and predictions, the successor to the Kyoto Protocol which should have been in place by 2012, has been delayed.”
It calls on global leaders, who will be meeting in Paris this December, to come to an “equitable and binding conclusion” and commit to a 100 % renewable energy and/or a zero emissions strategy.
The Islamic declaration follows a similar call to action by Pope Francis in his encyclical Laudato Si’ in June this year.
“All the faiths are talking about climate change,” says David Shreeve (via Nature), environmental advisor to the Church of England’s Archbishop’s Council. “It’s great that the Muslims are putting out a declaration, because whatever your faith, it’s a great opportunity for the faiths to stand up and say we really are concerned about this.”
The declaration ends with a reminder to all Muslims of a verse in the Qur’an –
Leading scientist says that even ambitious greenhouse gas reduction targets will not be able to save the world’s coral reefs.
Professor Peter Sale from the University of Windsor, Canada claims that coral reefs, as they were 50 years ago, cannot be saved from climate change – even if the climate change talks in December this year (COP21) are “wildly successful”.
Professor Sale unveiled the depressing results today at the Goldschmidt conference, a gathering of the world’s top geochemists in Prague.
He said, “Even if Paris is wildly successful, and a treaty is struck, ocean warming and ocean acidification are going to continue beyond the end of this century. This is now serious; I find it very unlikely that coral reefs, as I knew them in the mid-1960s, will still be found anywhere on this planet by mid-century. Instead, we will have algal-dominated, rubble-strewn, slowly eroding limestone benches.”
Globally coral reefs are generally found in tropical waters. Not only are they some of the world’s most productive ecosystems they also deliver ecosystem services in tourism, fisheries and coastline protection. The global economic value of coral reefs has been estimated to be US $375 billion per year!
Loss of reefs will be a fatal blow for the animals and communities who rely on them
While the global policy debate has been about trying to limit global warming to 2 degrees by the end of the century, Professor Sale claims that this won’t be enough to save coral reefs.
“I see little hope for reefs unless we embark on a more aggressive emissions reduction plan. Aiming for CO2 at 350ppm, or a total warming of around 1°C is scientifically defendable, and would give reefs a good chance; a number of coral reef scientists have called for this.”
“Knowing what we are doing, do we have the ethical right to eliminate an entire ecosystem from this planet? It’s never been done before. But watching as our actions lead to the loss of all coral reefs on the planet is like removing all rainforests. I don’t believe we have that right”.
“I believe there is such a thing as being too late.” – President Obama
Yesterday President Obama unveiled his “biggest, most important step” towards tackling the affects of climate change,
The proposed Clean Power Plan has been billed as the strongest action ever on climate change by a US president.
According to the proposed plans, the U.S. will cut levels of greenhouse gas emissions to a third of 2005 levels in the next 15 years. The measures include significant advancements in solar, wind and other renewable energy sources.
“No challenge poses a greater threat to our future, and future generations than a changing climate.” – President Obama
White House adviser Brian Deese said the Environmental Protection Agency (EPA) rules represented the “biggest step that any single president has made to curb the carbon pollution that is fuelling climate change”