Water staircases in seas:-
Internal waves, which move vertically through the ocean, can sometimes pass through “water staircases,” which are steplike variations of density of water, in such as manner as to churn up the underlying warm, salty water, thereby increasing the temperature of the top, cooler layers. This suggests a possible mechanism by which the upper layers of the Arctic Ocean warm up, causing the ice to melt.
Water staircases are steplike variations of density of water due to steplike changes in temperature and salinity. Though internal waves exist where the density gradually increases with depth, they cannot propagate where the density is uniform, for instance, within the steps of the staircase.
Ocean warming
The Arctic Ocean has inflows coming from the Pacific Ocean and Atlantic Ocean. In this, the top layers consist of cooler and less saline water and below that is a layer of water coming from the Atlantic Ocean which is more saline and warmer, too. The effect of salinity wins over that of temperature and so, though the water below is warmer, it is heavier than the cooler, less saline layer on top..
“Warm, but salty water — ultimately originating from the Atlantic Ocean resides near the bottom of the Arctic Ocean. If turbulence could somehow mix this water with that above, then, eventually, the surface could warm more rapidly, and this would increase the rate of sea-ice melt.
The internal movement of water within seas from cold, dense regions to warmer, lighter ones constitutes the largest observable waves. These can stretch to wavelengths of over a hundred metres and travel from top to bottom.
Like normal water waves, these propagate due to a variation of density of the water and not when there is constant density. In a staircase-like formation, though the density is constant within the step, there is a jump in density from one step to another. Hence, the wave’s energy can be transmitted from one interface to another.
Though not predominant, thermohaline staircases do occur in many places. “As well as the Arctic, they are persistent in the Caribbean Sea. This is due to surface heating and evaporation resulting in warm salty water overlying colder fresher water. They do not exist where there are strong currents, as in the Antarctic, which have enough energy to stir up any staircases that might form.
Selective filtering
So the scenario is that when an internal wave strikes a density staircase, a part of its energy may be transmitted through the staircase. In other words, density staircases in the ocean can act to reflect short wavelength internal waves and transmit longer wavelength waves. This is analogous to the selective transparency of glass windows on modern buildings that have multilayered coatings designed to reflect red light (long wavelength light) and allow green-blue (shorter wavelength) light through
On reaching the ocean floor, the long-wavelength waves which have been transmitted cause turbulence and mix up the water. The warm waters then rise to the top and warm the top layers.
“Strong storms passing over the Arctic typically generate waves on the order of 10-100 km horizontal scale. As sea-ice retreats and storms passing over the increasingly non-ice-covered ocean generate more and more waves, it seems that still a substantial fraction of this energy can transmit to depth, and this may consequently cause mixing at depth that could bring those deep warm (but salty) waters closer to the surface. The filtering that my theory predicts suggests that the energy transmitted to depth might be moderately smaller than one would expect in the absence of density staircases. But, for the most energetic waves — those transmitted by storms — the decrease is not substantial.
40 million Indians at risk from rising sea levels: UN report
Nearly 40 million Indians will be at risk from rising sea levels by 2050, with people in Mumbai and Kolkata having the maximum exposure to coastal flooding in future due to rapid urbanisation and economic growth, according to a UN environment report.
The ‘Global Environmental Outlook (GEO-6): Regional Assessments’ said the worst impacts of climate change are projected to occur in the Pacific and South and South-East Asia.
It said focussing on the population at risk from sea-level rise by 2050, seven of the 10 most vulnerable countries worldwide are in the Asia Pacific region.
India tops chart
India tops the chart with nearly 40 million people in the country projected to be at risk from rising sea levels, followed by more than 25 million in Bangladesh, over 20 million in China and nearly 15 million in the Philippines.
It said changes in settlement patterns, urbanisation and socio-economic status in Asia have influenced observed trends in vulnerability and exposure to climate extremes.
The report said in many coastal areas, growing urban settlements have also affected the ability of natural coastal systems to respond effectively to extreme climate events, rendering them more vulnerable.
“Some countries, such as China, India and Thailand, are projected to face increased future exposure to extremes, especially in highly urbanised areas, as a result of rapid urbanisation and economic growth,” it said.
It listed Mumbai and Kolkata in India, Guangzhou and Shanghai in China, Dhaka in Bangladesh, Yangon in Myanmar, Bangkok in Thailand, and Ho Chi Minh City and Hai Phong in Vietnam as projected to have the largest population exposure to coastal flooding in 2070.
The report, published ahead of the UN Environment Assembly taking place in Nairobi next week, said the worst impacts of climate change are projected to occur in the Pacific and South and Southeast Asia.
In 2011, six of the ten countries most vulnerable to climate change worldwide were in Asia and the Pacific.
On coastal areas highly exposed to cyclones and typhoons, the poor tend to be more exposed to natural disasters because they live on land open to hazards.
Combined impact
Evidence suggests that climate change and climate variability and sea-level rise will exacerbate multi-dimensional poverty in most developing countries.
By 2050, areas of storm surge zones are expected for Bangladesh, China, India, Indonesia, and the Philippines, with a combined total of over 58 million people at risk.
The UN report further said global urban populations are projected to increase by 2.5 billion by 2050, with nearly 90 per cent of the increase in Asia and Africa.
India fifth largest producer of e-waste: study
India, which has emerged as the world’s second largest mobile market, is also the fifth largest producer of e-waste, discarding roughly 18.5 lakh tonnes of electronic waste each year, a study says.
Telecom equipment alone accounts for 12 per cent of the e-waste, a joint study by Assocham-KPMG said.
Matter of concern
The rising levels of e-waste generation in India have been a matter of concern in recent years. With more than 100 crore mobile phones in circulation, nearly 25 per cent end up in e-waste annually, it said.
The Ministry of Environment, Forest and Climate Change has notified e-waste management rules, 2016, in which producers are for the first time covered under extended producers’ responsibility (EPR).
Waste collection target
The rules prescribe a waste collection target of 30 per cent waste generated under EPR for the first two years, progressively going up to 70 per cent in the seventh year of the rule.
The rules prescribe stringent financial penalties for non-compliance. However, the study said the unorganised sector in India is estimated to handle around 95 per cent of the e-waste produced in the country.
Given the huge user base and vast reach of telecom in India, it is practically difficult and expensive for the handset manufacturers to achieve the targets prescribed in the rules from first year, the study added.
ISRO plans to test air-breathing propulsion system
After successfully testing a technology demonstrator of a reusable launch vehicle, Indian Space Research Organisation (ISRO) is planning to test an air-breathing propulsion system, which aims to capitalise on the oxygen in the atmosphere instead of liquefied oxygen while in flight.
Generally, vehicles that are used to launch satellites use combustion of propellants with oxidiser and fuel. The air-breathing propulsion system aims at using oxygen present in the atmosphere up to 50 km from the earth’s surface to burn the fuel stored in the rocket.
Lower lift-off mass
The system, when implemented, would help in reducing the lift-off mass of the vehicle since liquefied oxygen need not be carried on board the vehicle. This would also help increasing the efficiency of the rocket and also make it cost-effective.
The new propulsion system, once mastered, would complement ISRO’s aim to develop a reusable launch vehicle that would have longer flight duration. The system, involving the scramjet engine, would become crucial while sending up the spacecraft.
ISRO is now evolving and testing various technologies to bring down the cost of launch vehicles. The national space agency has earlier developed rockets that can send multiple satellites in a single mission.
Ancient Mars hosted habitable environments: study
Scientists have found evidence for widespread buried deposits of iron- and calcium-rich carbonates on Mars, which suggests that the red planet once hosted habitable environments with liquid water.
Identification of these ancient carbonates and clays on Mars represents a window into history when the climate on Mars was very different from the cold and dry desert of today.
Carbonates beneath the surface of Mars point to a warmer and wetter environment in that planet’s past. The presence of liquid water could have fostered the emergence of life.
Subject of an energetic debate
The fate of water on Mars has been energetically debated by scientists because the planet is currently dry and cold, in contrast to the widespread fluvial features that etch much of its surface.
Scientists believe that if water did once flow on the surface of Mars, the planet’s bedrock should be full of carbonates and clays, which would be evidence that Mars once hosted habitable environments with liquid water.
And the carbon dioxide
Researchers have struggled to find physical evidence for carbonate-rich bedrock, which may have formed when carbon dioxide in the planet’s early atmosphere was trapped in ancient surface waters. They have focused their search on Mars’ Huygens basin.
This feature is an ideal site to study carbonates because multiple impact craters and troughs have exposed ancient, subsurface materials where carbonates can be detected across a broad region, researchers have said.
Outcrops in the 450-km wide Huygens basin contain both clay minerals and iron- or calcium-rich carbonate-bearing rocks.
Carbonate-bearing rocks
The study has highlighted evidence of carbonate-bearing rocks in multiple sites across Mars, including Lucaya crater, where carbonates and clays 3.8 billion years old were buried by as much as 5 km of lava and caprock.
The researchers identified carbonates on the planet using data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), which is on the Mars Reconnaissance Orbiter. This instrument collects the spectral fingerprints of carbonates and other minerals through vibrational transitions of the molecules in their crystal structure that produce infrared emission.
Geologic features
The team paired CRISM data with images from the High Resolution Imaging Science Experiment (HiRISE) and Context Camera (CTX) on the orbiter, as well as the Mars Orbiter Laser Altimeter (MOLA) on the Mars Global Surveyor, to gain insights into the geologic features associated with carbonate-bearing rocks.
The extent of the global distribution of martian carbonates is not yet fully resolved and the early climate on the red planet is still subject of debate.
However, this study is a forward step in understanding the potential habitability of ancient Mars.
Recent Posts
The United Nations has shaped so much of global co-operation and regulation that we wouldn’t recognise our world today without the UN’s pervasive role in it. So many small details of our lives – such as postage and copyright laws – are subject to international co-operation nurtured by the UN.
In its 75th year, however, the UN is in a difficult moment as the world faces climate crisis, a global pandemic, great power competition, trade wars, economic depression and a wider breakdown in international co-operation.
Still, the UN has faced tough times before – over many decades during the Cold War, the Security Council was crippled by deep tensions between the US and the Soviet Union. The UN is not as sidelined or divided today as it was then. However, as the relationship between China and the US sours, the achievements of global co-operation are being eroded.
The way in which people speak about the UN often implies a level of coherence and bureaucratic independence that the UN rarely possesses. A failure of the UN is normally better understood as a failure of international co-operation.
We see this recently in the UN’s inability to deal with crises from the ethnic cleansing of the Rohingya Muslims in Myanmar, to civil conflict in Syria, and the failure of the Security Council to adopt a COVID-19 resolution calling for ceasefires in conflict zones and a co-operative international response to the pandemic.
The UN administration is not primarily to blame for these failures; rather, the problem is the great powers – in the case of COVID-19, China and the US – refusing to co-operate.
Where states fail to agree, the UN is powerless to act.
Marking the 75th anniversary of the official formation of the UN, when 50 founding nations signed the UN Charter on June 26, 1945, we look at some of its key triumphs and resounding failures.
Five successes
1. Peacekeeping
The United Nations was created with the goal of being a collective security organisation. The UN Charter establishes that the use of force is only lawful either in self-defence or if authorised by the UN Security Council. The Security Council’s five permanent members, being China, US, UK, Russia and France, can veto any such resolution.
The UN’s consistent role in seeking to manage conflict is one of its greatest successes.
A key component of this role is peacekeeping. The UN under its second secretary-general, the Swedish statesman Dag Hammarskjöld – who was posthumously awarded the Nobel Peace prize after he died in a suspicious plane crash – created the concept of peacekeeping. Hammarskjöld was responding to the 1956 Suez Crisis, in which the US opposed the invasion of Egypt by its allies Israel, France and the UK.
UN peacekeeping missions involve the use of impartial and armed UN forces, drawn from member states, to stabilise fragile situations. “The essence of peacekeeping is the use of soldiers as a catalyst for peace rather than as the instruments of war,” said then UN Secretary-General Javier Pérez de Cuéllar, when the forces won the 1988 Nobel Peace Prize following missions in conflict zones in the Middle East, Africa, Asia, Central America and Europe.
However, peacekeeping also counts among the UN’s major failures.
2. Law of the Sea
Negotiated between 1973 and 1982, the UN Convention on the Law of the Sea (UNCLOS) set up the current international law of the seas. It defines states’ rights and creates concepts such as exclusive economic zones, as well as procedures for the settling of disputes, new arrangements for governing deep sea bed mining, and importantly, new provisions for the protection of marine resources and ocean conservation.
Mostly, countries have abided by the convention. There are various disputes that China has over the East and South China Seas which present a conflict between power and law, in that although UNCLOS creates mechanisms for resolving disputes, a powerful state isn’t necessarily going to submit to those mechanisms.
Secondly, on the conservation front, although UNCLOS is a huge step forward, it has failed to adequately protect oceans that are outside any state’s control. Ocean ecosystems have been dramatically transformed through overfishing. This is an ecological catastrophe that UNCLOS has slowed, but failed to address comprehensively.
3. Decolonisation
The idea of racial equality and of a people’s right to self-determination was discussed in the wake of World War I and rejected. After World War II, however, those principles were endorsed within the UN system, and the Trusteeship Council, which monitored the process of decolonisation, was one of the initial bodies of the UN.
Although many national independence movements only won liberation through bloody conflicts, the UN has overseen a process of decolonisation that has transformed international politics. In 1945, around one third of the world’s population lived under colonial rule. Today, there are less than 2 million people living in colonies.
When it comes to the world’s First Nations, however, the UN generally has done little to address their concerns, aside from the non-binding UN Declaration on the Rights of Indigenous Peoples of 2007.
4. Human rights
The Human Rights Declaration of 1948 for the first time set out fundamental human rights to be universally protected, recognising that the “inherent dignity and of the equal and inalienable rights of all members of the human family is the foundation of freedom, justice and peace in the world”.
Since 1948, 10 human rights treaties have been adopted – including conventions on the rights of children and migrant workers, and against torture and discrimination based on gender and race – each monitored by its own committee of independent experts.
The language of human rights has created a new framework for thinking about the relationship between the individual, the state and the international system. Although some people would prefer that political movements focus on ‘liberation’ rather than ‘rights’, the idea of human rights has made the individual person a focus of national and international attention.
5. Free trade
Depending on your politics, you might view the World Trade Organisation as a huge success, or a huge failure.
The WTO creates a near-binding system of international trade law with a clear and efficient dispute resolution process.
The majority Australian consensus is that the WTO is a success because it has been good for Australian famers especially, through its winding back of subsidies and tariffs.
However, the WTO enabled an era of globalisation which is now politically controversial.
Recently, the US has sought to disrupt the system. In addition to the trade war with China, the Trump Administration has also refused to appoint tribunal members to the WTO’s Appellate Body, so it has crippled the dispute resolution process. Of course, the Trump Administration is not the first to take issue with China’s trade strategies, which include subsidises for ‘State Owned Enterprises’ and demands that foreign firms transfer intellectual property in exchange for market access.
The existence of the UN has created a forum where nations can discuss new problems, and climate change is one of them. The Intergovernmental Panel on Climate Change (IPCC) was set up in 1988 to assess climate science and provide policymakers with assessments and options. In 1992, the UN Framework Convention on Climate Change created a permanent forum for negotiations.
However, despite an international scientific body in the IPCC, and 165 signatory nations to the climate treaty, global greenhouse gas emissions have continued to increase.
Under the Paris Agreement, even if every country meets its greenhouse gas emission targets we are still on track for ‘dangerous warming’. Yet, no major country is even on track to meet its targets; while emissions will probably decline this year as a result of COVID-19, atmospheric concentrations of greenhouse gases will still increase.
This illustrates a core conundrum of the UN in that it opens the possibility of global cooperation, but is unable to constrain states from pursuing their narrowly conceived self-interests. Deep co-operation remains challenging.
Five failures of the UN
1. Peacekeeping
During the Bosnian War, Dutch peacekeeping forces stationed in the town of Srebrenica, declared a ‘safe area’ by the UN in 1993, failed in 1995 to stop the massacre of more than 8000 Muslim men and boys by Bosnian Serb forces. This is one of the most widely discussed examples of the failures of international peacekeeping operations.
On the massacre’s 10th anniversary, then UN Secretary General Kofi Annan wrote that the UN had “made serious errors of judgement, rooted in a philosophy of impartiality”, contributing to a mass murder that would “haunt our history forever”.
If you look at some of the other infamous failures of peacekeeping missions – in places such as Rwanda, Somalia and Angola – it is the limited powers given to peacekeeping operations that have resulted in those failures.
2. The invasion of Iraq
The invasion of Iraq by the US in 2003, which was unlawful and without Security Council authorisation, reflects the fact that the UN is has very limited capacity to constrain the actions of great powers.
The Security Council designers created the veto power so that any of the five permanent members could reject a Council resolution, so in that way it is programmed to fail when a great power really wants to do something that the international community generally condemns.
In the case of the Iraq invasion, the US didn’t veto a resolution, but rather sought authorisation that it did not get. The UN, if you go by the idea of collective security, should have responded by defending Iraq against this unlawful use of force.
The invasion proved a humanitarian disaster with the loss of more than 400,000 lives, and many believe that it led to the emergence of the terrorist Islamic State.
3. Refugee crises
The UN brokered the 1951 Refugee Convention to address the plight of people displaced in Europe due to World War II; years later, the 1967 Protocol removed time and geographical restrictions so that the Convention can now apply universally (although many countries in Asia have refused to sign it, owing in part to its Eurocentric origins).
Despite these treaties, and the work of the UN High Commission for Refugees, there is somewhere between 30 and 40 million refugees, many of them, such as many Palestinians, living for decades outside their homelands. This is in addition to more than 40 million people displaced within their own countries.
While for a long time refugee numbers were reducing, in recent years, particularly driven by the Syrian conflict, there have been increases in the number of people being displaced.
During the COVID-19 crisis, boatloads of Rohingya refugees were turned away by port after port. This tragedy has echoes of pre-World War II when ships of Jewish refugees fleeing Nazi Germany were refused entry by multiple countries.
And as a catastrophe of a different kind looms, there is no international framework in place for responding to people who will be displaced by rising seas and other effects of climate change.
4. Conflicts without end
Across the world, there is a shopping list of unresolved civil conflicts and disputed territories.
Palestine and Kashmir are two of the longest-running failures of the UN to resolve disputed lands. More recent, ongoing conflicts include the civil wars in Syria and Yemen.
The common denominator of unresolved conflicts is either division among the great powers, or a lack of international interest due to the geopolitical stakes not being sufficiently high. For instance, the inaction during the Rwandan civil war in the 1990s was not due to a division among great powers, but rather a lack of political will to engage.
In Syria, by contrast, Russia and the US have opposing interests and back opposing sides: Russia backs the government of the Syrian dictator Bashar al-Assad, whereas the US does not.
5. Acting like it’s 1945
The UN is increasingly out of step with the reality of geopolitics today.
The permanent members of the Security Council reflect the division of power internationally at the end of World War II. The continuing exclusion of Germany, Japan, and rising powers such as India and Indonesia, reflects the failure to reflect the changing balance of power.
Also, bodies such as the IMF and the World Bank, which are part of the UN system, continue to be dominated by the West. In response, China has created potential rival institutions such as the Asian Infrastructure Investment Bank.
Western domination of UN institutions undermines their credibility. However, a more fundamental problem is that institutions designed in 1945 are a poor fit with the systemic global challenges – of which climate change is foremost – that we face today.