CFC ban bought us time to fight climate change

 From The BBC

A worldwide ban on ozone-depleting chemicals in 1987 has averted a climate catastrophe today, scientists say.

The Montreal Protocol on Substances that Deplete the Ozone Layer, banning chemicals such as chlorofluorocarbons, has now simulated our "world avoided".

Without the treaty, Earth and its flora would have been exposed to far more of the Sun's ultraviolet (UV) radiation.

Former UN Secretary General Kofi Annan has called it "perhaps the single most successful international agreement".

Continued and increased use of chlorofluorocarbons (CFCs) would have contributed to global air temperatures rising by an additional 2.5°C by the end of this century, the international team of scientists found.

Part of that would have been caused directly by CFCs, which are also potent greenhouse gases. [Producing CFCs on Mars has been proposed as a way of terraforming Mars and raising its surface temperature.]

But the damage they cause the ozone layer would also have released additional planet-heating carbon dioxide - currently locked up in vegetation - into the atmosphere.

"In past experiments, people have exposed plants - basically tortured plants - with high levels of UV," lead researcher Dr Paul Young, of the Lancaster Environment Centre, said.

The scientists estimated there would be:

• 580 billion tonnes less carbon stored in forests, other vegetation and soils
• an extra 165-215 parts per million (40-50%) of carbon dioxide in the atmosphere

"What we see in our 'world-avoided experiment' is an additional 2.5C warming above any warming that we would get from greenhouse-gas increases," Dr Young said.

But similar collective action to limit greenhouse-gas emissions was likely to be much more challenging.

"The science was listened to and acted upon - we have not seen that to the same degree with climate change," he told BBC Radio 4's Inside Science programme.

The experiment could appear to suggest hope for an "alternative future" that had avoided the worst consequences of climate change.

"But I would be cautious of using it as a positive example for the climate negotiations," Dr Young said.

"It's not [directly] comparable - but it's nice to have something positive to hold on to and to see that the world can come together."

The ozone hole over Antarctica, in 2000

The electric industry's dirty secret

From The BBC.

It's the most powerful greenhouse gas known to humanity, and emissions have risen rapidly in recent years, the BBC has learned.

Sulphur hexafluoride, or SF6, is widely used in the electrical industry to prevent short circuits and accidents.

But leaks of the little-known gas in the UK and the rest of the EU in 2017 were the equivalent of putting an extra 1.3 million cars on the road.  Levels are rising as an unintended consequence of the green energy boom.

Cheap and non-flammable, SF6 is a colourless, odourless, synthetic gas. It makes a hugely effective insulating material for medium and high-voltage electrical installations.  It is widely used across the industry, from large power stations to wind turbines to electrical sub-stations in towns and cities. It prevents electrical accidents and fires.

However, the significant downside to using the gas is that it has the highest global warming potential of any known substance. It is 23,500 times more warming than carbon dioxide (CO2).  It also persists in the atmosphere for a long time, warming the Earth for at least 1,000 years.

"As renewable projects are getting bigger and bigger, we have had to use it within wind turbines specifically," said Costa Pirgousis, an engineer with Scottish Power Renewables on its new East Anglia wind farm, which doesn't use SF6 in turbines.  "As we are putting in more and more turbines, we need more and more switchgear and, as a result, more SF6 is being introduced into big turbines off shore.  It's been proven for years and we know how it works, and as a result it is very reliable and very low maintenance for us offshore."

Across the entire UK network of power lines and substations, there are around one million kilograms of SF6 installed.  A study from the University of Cardiff found that across all transmission and distribution networks, the amount used was increasing by 30-40 tonnes per year.  This rise was also reflected across Europe with total emissions from the 28 member states in 2017 equivalent to 6.73 million tonnes of CO2. That's the same as the emissions from 1.3 million extra cars on the road for a year.

Just one kilogram of SF6 warms the Earth to the same extent as 24 people flying London to New York return.

Source: The BBC

The most important means by which SF6 gets into the atmosphere is from leaks in the electricity industry.

Electrical company Eaton, which manufactures switchgear without SF6, says its research indicates that for the full life-cycle of the product, leaks could be as high as 15% - much higher than many other estimates.

Louis Shaffer, electrical business manager at Eaton, said: "The newer gear has very low leak rates but the key question is do you have newer gear?   We looked at all equipment and looked at the average of all those leak rates, and we didn't see people taking into account the filling of the gas. Plus, we looked at how you recycle it and return it and also included the catastrophic leaks."

Developed countries are expected to report every year to the UN on how much SF6 they use, but developing countries do not face any restrictions on use.  Right now, scientists are detecting concentrations in the atmosphere that are 10 times the amount declared by countries in their reports. Scientists say this is not all coming from countries like India, China and South Korea.

The question of alternatives to SF6 has been contentious over recent years.

For high-voltage applications, experts say there are very few solutions that have been rigorously tested.

"There is no real alternative that is proven," said Prof Manu Haddad from the school of engineering at Cardiff University.  "There are some that are being proposed now but to prove their operation over a long period of time is a risk that many companies don't want to take."

However, for medium voltage operations there are several tried-and-tested materials. Some in the industry say that the conservative nature of the electrical industry is the key reason that few want to change to a less harmful alternative.  "I will tell you, everyone in this industry knows you can do this; there is not a technical reason not to do it," said Louis Shaffer from Eaton.

"It's not really economic; it's more a question that change takes effort and if you don't have to, you won't do it."  One study found that the methods used to calculate emissions in richer countries "severely under-reported" emissions over the past two decades.

It's obvious, isn't it?  We're going to have to stop using it.  It's going to have to be replaced.   Ironically, it will be perfect for terraforming Mars, because of its potency and 1000-year life.  CFCs (also fluorine compounds and potent greenhouse gases) will degrade too quickly on Mars because of the UV-flux.  But seriously, do we want to raise Earth's temperature by 10 degrees C?

Hansen: projections and reality

It's been 30 years since Jim Hansen warned us about global warming.  "The greenhouse effect is here", he said on 23rd June 1988 to the US Senate.  What have we done since then?

The first chart below shows the three scenarios projected by Hansen back in 1988.  Scenario A has the highest growth in CO2, NO2, methane and CFCs, scenario B lower rates and scenario C projected stability, i.e., no increase in greenhouse gases. 

And at first you'll say, but hang on, his projected temperature is much higher than what actually happened.  The model was wrong!  Um, no.  Remember that to get these results his team had to project what would happen to the inputs to the model, i.e., the emissions/levels of the greenhouse gases I mentioned above.  Actual CO2 turned out to be pretty much what Hansen and co projected they would be.  But Hansen projected ongoing rises in CFCs , which are very powerful greenhouse gases.  In a rare win for co-operation and good sense, CFCs were phased out of production after the Montreal Protocol came into force in 1988.  If Hansen had factored in the levelling off in CFCs  in the atmosphere, he would have got a result quite close to what actually happened (see the second chart below).

(Source for both charts: RealClimate)

There's good and bad news from all this. 

The good news is that the world actually agreed to phasing out CFCs back in 1988, and that saved us 0.5 degrees C of global warming.   If we could agree then, we might yet be able to agree with CO2 and NO2.  Yes, fossil fuel industries now are bigger and more powerful than CFC industries were then, and yes, that well hadn't been poisoned by the Right's demented passion for coal.  But the power of coal and oil industries is dwindling.  The evidence of global warming gets every day more scary.  Most ordinary people, as opposed to politicians, are convinced that global warming is real and that we need to do something about it.  And the costs of renewables have fallen and keep on falling so precipitously that the switch to renewables is happening anyway, despite the rantings of the Right.  The opposition to a genuine climate agreement with teeth is diminishing, while the necessity for it grows every day more pressing.

The bad news is that Hansen's scenario C, which assumed that production of all greenhouse gases would stop immediately, still had temperatures rise by 0.5 degrees over the next 20 years, before slowly starting to decline.  This is because there are lags in the system.  For example, daily temperatures don't peak at midday when insolation is at its peak but a few hours later, when the sun's power is already waning.  These lags mean that even if we cut output of greenhouse gases to zero by 2050, temperatures will likely go on rising by another 0.5 degrees C up to 2070 before starting to gradually decline.  And by 2050, temperatures will already have risen another 0.6 degrees from the greenhouse gases which we will continue to emit into the atmosphere up till then.  So that means another 1.1 degree C rise in global temperatures.  The 1 degree we have had so far is bad enough.  What will another 1 degree do?

[Read more here]