HFCs (Hydrofluorocarbons) are a popular choice by refrigeration manufacturers of because they are are deemed to be a "like-for-like" replacement substance for Chlorofluorocarbons (CFCs) and hydrofluorochlorocarbons (HCFCs), which are banned or being phased out under the Montreal Protocol on Substances that Deplete the Ozone Layer.
The substances have also been widely used as aerosol propellants and solvents.
Closing the gap
The Protocol came into force in 1989 after it was discovered that a group of gases, such as CFCs and HCFCs, were responsible for creating a "hole" in the Ozone Layer - a region of the atmosphere about 20-30km above the Earth's surface, which protects life below from harmful levels of ultraviolet light produced by the Sun.
The Montreal Protocol is deemed to the most successful international policy mechanism of its kind. By 2009, it had phased out the consumption of 98% of the chemicals controlled by the protocol.
However, the replacement substances - HFCs - act as greenhouse gases in the atmosphere.
So while they do not harm the Ozone Layer, experts have warned that their growing popularity could lead to an accumulation that could hamper efforts to limit human-induced global warming.
"While these 'replacement for replacement' chemicals cause near zero damage to the ozone layer, they are powerful greenhouse gases in their own right," observed Achim Steiner, Unep executive director.
The report's authors said that not all HFCs had the same impact on the climate.
"Their differing ability is mostly [a result of] differences in their atmospheric lifetimes, which determine how much they accumulate in the atmosphere," they explained.
"HFCs with lifetimes greater than a few years accumulate more... and have larger climate consequences.
"Of concern is the fact that the average global warming potential (GWP) of the current mix of HFCs being used is about 1,600, meaning that a kilogram of currently used HFC has about 1,600 times the effect on global warming as a kilogram of carbon dioxide."
The team said that the rise in the global consumption of HFCs is projected to rise primarily because of the growing demand from emerging economies and a growing global population.
The authors point to a number of possible solutions to limit the substances' influence on the climate system, including:
alternative methods or processes; ranging from improved building designs in order to reduce the need for air-conditioning units to the use of fibre rather than foam insulation material,
greater use of non-HFC substance, a number of which are already commercially available,
"climate-friendly HFCs" - ones the shorter lifetimes in the atmosphere (months rather than years).
The report added that updating global standards, investment incentives and technical training programmes would help accelerate the introduction of alternative substances.
As the Democratic Republic of Congo prepares for just its second general elections in four decades on 28 November, Congolese affairs analyst Theodore Trefon considers whether this failed state, still recovering from a war which led to an estimated four million deaths, can ever be rebuilt.
People in the Democratic Republic of Congo expect very little from the state, government or civil servants.
In fact, ordinary Congolese often repeat expressions like "the state is dying but not yet dead" or "the state is ever present but completely useless".
It seems they also expect little from the upcoming elections and there can be little argument that DR Congo is indeed a failed state.
Ordinary citizens are poor, hungry and under-informed.
The government is unable to provide decent education or health services.
The country - two-thirds of the size of western Europe - is a battleground.
The citizens of DR Congo pray to be delivered from the brutal militias that still control parts of the eastern provinces, where rape has become so commonplace that one senior UN official called the country "the rape capital of the world".
"When you are rock bottom, you can still dig deeper," was his response.
Public administration is in shambles. Civil servants have mutated into predators.
Ferdinand Munguna is a retired railway worker in Lubumbashi, the mineral capital of DR Congo in the south of the country.
He has to bribe the man working in the pension office who requires "motivation" before processing the old man's file. Mr Munguna complains that his pension is "hardly enough to buy soap".
Starting a business in DR Congo takes 65 days compared to the sub-Saharan African average of 40 days. In neighbouring Rwanda it takes three days.
And guess which country has one of the worst air safety records worldwide?
The prestigious Foreign Policy magazine's Failed States Index puts DR Congo in the critically failed category. Only Somalia, Chad and Sudan (when it included South Sudan) have worse rankings.
DR Congo, Africa's second largest country, has a literacy rate of 67%
On the political front, President Joseph Kabila has shown much more interest in regime consolidation than implementing his five-point development agenda - which most Congolese consider more as a political slogan than a development initiative.
When criticised, Mr Kabila's henchmen resort to the ultimate force of dissuasion.
Take Zoe Kabila, the president's brother, who ordered his Republican Guard escort to beat up two traffic officers because they did not give his 4X4 priority.
Usually immune to the brutality of the security forces, even people in Kinshasa were shocked by this incident at a busy downtown intersection.
Numerous cases of journalist beatings and killings have also been reported.
Floribert Chebeya, a highly respected human rights activist was murdered, allegedly by members of the president's inner circle.
In the absence of a functioning state or similar, even the best-intended projects can have perverse side effects if they are carried out without comprehensive feasibility studies or efforts to understand local culture and practices.
An international medical NGO provided mosquito nets to a poor village in the Upemba region of Katanga. Many lakeside villages in the mineral-rich province suffer from a high rate of malaria-induced child mortality. Sleeping inside these nets is the best way to avoid mosquito bites and malaria. But this laudable action created a human and ecological catastrophe.
As the mosquito nets were free and abundant, fisherman used them as fishing nets. Given their extremely fine mesh, not only were fish removed from the lake but all other forms of micro-fauna and micro-flora too. The lake gradually became covered with a black scum. Villagers lost their sources of livelihood and food supply.
It took a Belgian priest two years to get the villagers, who believed they had been cursed, to realise what had happened and before the lake was able to regenerate.
There are few figures on the political landscape with vision, leaders able to bring an end to corrupt government, reduce poverty, solve the country's security problems or improve the well-being of ordinary people.
DR Congo bashing has become a mantra amongst academics, humanitarian non-governmental organisations (NGOs) and policy makers.
But I think that this is unfair.
While it is important to maintain pressure on Kinshasa's unabashedly corrupt political establishment, we also have to consider the country's troubled past.
Few societies have accumulated so many woes.
Those old enough to remember say the whip and chain is what they associate most with Belgian colonialism.
Others however are nostalgic and wish for the Belgians to return to solve the country's problems.
Cold War policies facilitated the maintenance of the brutal dictatorship of Mobutu Sese Seko.
BBC Afrique's Arthur Malu Malu Mushi explains the key issues as DR Congo chooses a new president
He ruled what was then named Zaire for 32 years, supported by the West because of Cold War strategic interests.
Two wars - the liberation war that toppled Mobutu and "Africa's first world war", from 1997-2002 - are overwhelming obstacles to development, state-building and well-being.
DR Congo is also victim to what is commonly referred to as "the resource curse". The central government cannot control borders with its nine neighbours.
Much of DR Congo's coltan, a mineral used in computers and mobiles, is illegally exported through Rwanda. Precious tropical hardwoods are siphoned off through Uganda.
Surreal
DR Congo's financial and technical partners - the so called "international community" - are also to blame.
They have no master plan for reform. They do not share a common vision and often implement contradictory programmes.
Belgium supported the idea of decentralisation arguing that it could bring government accountability down to the grassroots level. The World Bank blocked the process.
DR Congo's road to development is paved with good intentions
Bank experts have some control of the treasury in Kinshasa but they have absolutely no idea of how resources in the provinces are managed.
Data collection is a surreal concept in DR Congo - many offices do not have electricity, let alone computers.
Absence of national sovereignty is another hallmark of a failed state.
DR Congo is a country under international trusteeship. Important decisions are taken by World Bank technocrats, UN officials and increasingly by international NGOs.
When the electoral campaign officially opened last month, candidates travelled to Europe and the US to garner support.
The UN mission, Monusco, is playing a key logistical role in the elections by transporting ballot boxes across the vast nation. People would not be able to vote without this kind of support.
Whatever accountability there is in DR Congo is directed towards international backers, not the Congolese people.
Congolese authorities have abdicated from the development agenda.
Road rehabilitation and bridge building have been delegated to the World Bank and Belgian Technical Cooperation.
Monusco is supposed to look after the security sector. The World Health Organization and medical NGOs try to deal with the public health challenges.
The UK is involved in reinforcing governance programmes, while churches provide primary education.
The state is an absentee landlord - outside partners do its work.
Dynamic survivors
So DR Congo is on an artificial life-support system. But replacing the state, or acting on its behalf, is not viable in the long-term. It undermines state-building momentum.
UN human development index: Bottom of 187 countries surveyed
Life expectancy: 48 years
Has 70% of the globe's coltan - vital for mobile phones
Average annual income: $300
With 13% of the world's hydropower potential, its network of rivers could power much of Africa
Just 9% of the population has access to electricity
Sources: Estimated figures from the UN and World Bank
DR Congo and its partners are clearly confronted by the tragedy of powerlessness.
The system is such that when things do not work, go wrong or do not move forward, it is never really anyone's fault.
There are plenty of good excuses. A colleague told me when asked why he did not show up for an appointment: "Well, there was an eclipse that day."
While DR Congo is clearly a failed state, Congolese society has not failed.
On the contrary it is strong, vibrant, dynamic, tolerant and generous. People have a sense of taking charge of their own destinies.
Women form rotating credit systems to compensate for the absence of an accessible banking system.
Farmers band together to hire a lorry to get their cassava or charcoal from the central city of Kikwit to market in Kinshasa.
Bebe, who lives in the Paris suburb of Griney, sends money home to Kasai via Western Union. Some months it contributes to school fees, others it pays for medicines for her ailing mother-in-law.
Her father will spend some of it on Primus, the beer of choice in Kinshasa.
"Elikia" means hope in Lingala and there is much of it throughout the country.
Hopes for positive change will come from the people, not from the Congolese political establishment, and certainly not from outside interventions.
Last month Home Secretary Theresa May sparked a row over a man who could not be deported "because he had a pet cat".
The judiciary said the cat was not a factor in the man's right to stay.
Mr Clarke became embroiled in a row with Ms May over the cat story.
But there have been a number of deportation cases which have outraged government ministers.
Family life 'right'
In December 2009 attempts to deport Aso Mohammed Ibrahim, an Iraqi Kurd, failed because human rights legislation entitled him to a "family life" in UK.
Ibrahim knocked down and killed Amy Houston, 12, in Blackburn, Lancashire, in 2003 and was later jailed for driving while disqualified.
Mr Clarke said the deal with the European Court of Human Rights might be agreed at a conference in London in April 2012.
He said it would stop the situation where "everybody who's just lost his arguments about deportation should be able to go there and get in the queue, wait a few years to get it all reheard again when he's lost the argument three times already" in the UK.
Mr Clarke told the Telegraph: "What we are trying to do is get the role of the court sorted out so that it deals with serious human rights issues of the kind that require an international court.
"We want the court back to its proper business as an international court which takes up serious issues of principle."
Britain took over chairmanship of the Council of Europe, which oversees the court, earlier this month.
'Pig's ear'
Mr Clarke said: "A lot of member states have been pushing for similar things, and a lot of them believe a British chairmanship is the best time to deliver it, and they think we're the best hope of drawing this to a conclusion.
"The term human rights, it gets misused. There is a tendency in this country for the words human rights to get thrown about as much as health and safety. Both of them get hopelessly misused."
He added: "When some official, some policeman, whoever, has made some mistake in taking some absurd decision, the first thing they do to fend off criticism is to blame it on health and safety and blame it on human rights. The truth is that someone's made a pig's ear in the office."
On Monday, England and Wales' top judge said courts have tended to interpret the judgements of the European Court of Human Rights "too closely".
Lord Judge said a lot of ECHR rulings related only to specific cases and did not set wider legal precedents.
The Conservatives want to replace the Human Rights Act (HRA) - through which the European Convention is incorporated into UK law - with a British Bill of Rights but Lib Dem leader Nick Clegg has insisted the HRA must remain in force.
Brazilian police are investigating an oil spill in an offshore field operated by the US company Chevron.
Ships are working to disperse the slick 120km (75 miles) off the coast of Rio de Janeiro state, and Chevron says it has plugged the oil well.
Brazil's Energy Minister Edison Lobao has said the company will be "severely punished" if it is found to have failed in its environmental responsibilities.
In recent years Brazil has discovered huge oil reserves in the Atlantic.
The oil is leaking from a well in the Frade oil project, 370km (230 miles) off the Brazilian coast.
Chevron initially estimated that 400-650 barrels of oil had formed a sheen on the water after seeping from the seabed near the well.
But the international environmental group Skytruth said satellite images suggested the spill was many times bigger.
Brazilian energy minister Edison Lobao said the spill "was not as serious as had been announced" and was not moving towards the Brazilian coast.
But he said Brazil's oil agency ANP was monitoring the situation closely and would apply the full force of the law.
"If Chevron is not fulfilling its responsibilities, it will be more severely punished," he said.
ANP said underwater images showed Chevron's effort to permanently seal the well with cement appeared to have been successful, although there appeared to be a residual flow of oil from the seabed.
"The slick is continuing to move away from the coast and dispersing, as is desired," it added.
'Bad faith'
Police environment experts have been sent on navy helicopters to assess the scale of the spill.
Green Party members of the Brazilian Congress have called for a debate on the matter.
Federal deputy Jose Sarney Filho said Chevron appeared to have underplayed the scale of the accident.
"What has alarmed us is the lack of transparency on the part of the company and the attempt to minimise the size of the disaster," he told the official news agency Agencia Brasil.
"This is a clear demonstration of bad faith," he added.
Chevron said on Thursday the flow of oil from the ocean floor has been reduced to "infrequent droplets" and the remaining oil sheen on the surface was estimated at less than 65 barrels.
"Chevron continues to fully inform and work with Brazilian government agencies and industry partners on all aspects of this matter," the company said in a statement.
In recent years Brazil has discovered billions of barrels of oil in deep water that could make it one of the world's top five producers.
So far there has been little public debate about the environmental dangers of offshore drilling.
Political discussion has instead focused on how future oil revenues should be divided between different states.
While progress has been made to protect the ozone layer, experts say more needs to be done
