Arctic Sea Ice : Forum

AGW in general => Science => Topic started by: ArcticMelt2 on July 07, 2019, 04:20:38 PM

Title: Little known greenhouse gases
Post by: ArcticMelt2 on July 07, 2019, 04:20:38 PM
As you know, now the main struggle is with emissions of carbon dioxide and methane. But the chemical industry produces many other gases that have greenhouse properties. Their influence on climate can be comparable to CO2 and CH4.

(H)CFCs are ozone depleting substances (ODSs) and have been successfully been phased out under the Montreal Protocol. As a result, the abundance of ODSs in the atmosphere has declined and the ozone layer is expected to recover. CFCs also had higher Global Warming Potentials (GWPs) than the HFCs replacing them. As such, by replacing CFCs by HFCs, the refrigeration and air-conditioning industry and other users not only contributed to the preservation of the ozone layer, but also made a most significant and positive contribution to reducing greenhouse gas emissions. Their reduction would represent about four times the objective of the Kyoto Protocol. In 1990, CFCs represented 25 per cent of global greenhouse gas emissions. In 2002, the emissions from the use of HFCs were about 0.5 % of total global GHG emissions and according to the US NOAA (National Oceanic and Atmospheric Administration), which provides annual updates of the AGGI (Annual Greenhouse Gas Index), intended to follow the evolution of the radiative forcing (ability of all greenhouse gases to trap heat) of greenhouse gases, the HFC impact in 2016, was 0.89 % of the total GHG emissions.


In the 1980s, scientists discovered that the earth’s protective ozone layer was thinning, raising the risk of skin cancer and cataracts. The culprits were chlorofluorocarbons (CFC), chemical substances widely used in spray cans, refrigeration and air conditioning equipment, and heretofore considered as safe because they are non-toxic, not inflammable and not explosive.

The international community reacted quickly and adopted the Montreal protocol in 1987, which phases out ozone-destroying substances. However, it turns out that the F-gases which replace CFCs contribute to global warming, having a global warming potential up to 23 000 times higher than CO2. F-gases account for around 2% of the EU’s greenhouse gas emissions.

The worldwide use of F-gases has grown rapidly and reached almost 500 million tonnes CO2e (carbon dioxide equivalent) in 2005. The rapid growth is expected to continue with growing demand for refrigeration and air conditioning, especially in developing countries. By 2050, F-gases could account for 8% of global greenhouse gas emissions.

Refrigerant leaks in mobile air conditioning systems are common and hard to prevent. To reduce the climate impacts from air condition in vehicles, the Mobile Air Conditioning (MAC) Directive requires that new cars be equipped with air conditioning systems that use more climate-friendly refrigerants. However,  Mercedes-Benz recently discovered that the relatively climate-friendly refrigerant R1234xy can catch fire in a car crash. The company intends to continue using HFC-134a, whose global warming potential 1320 times higher than CO2, and risks infringement proceedings for violation of the MAC Directive.


Projections for global f-gas emissions 2005-2050. Source: Umweltbundesamt
Title: Re: Little known greenhouse gases
Post by: ArcticMelt2 on July 07, 2019, 04:26:18 PM
In general, taking into account all greenhouse gases and deforestation, the total impact on the climate now reaches nearly 60 billion tons of carbon dioxide per year.


Global greenhouse gas emissions show no signs of peaking. Global CO2 emissions from energy and industry increased in 2017, following a three-year period of stabilization. Total annual greenhouse gases emissions, including from land-use change, reached a record high of 53.5 GtCO2e in 2017, an increase of 0.7 GtCO2e compared with 2016.
Fluorinated gases (hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6)) are only responsible for 2.4 percent of total GHG emissions and continue to have strong growth at around 5 percent/year. The Kigali Amendment to the
Montreal Protocol on Substances that Deplete the Ozone Layer aims for the phase-down of hydrofluorocarbons (HFCs) by cutting their production and consumption.

Global greenhouse gas emissions per type of gas
LUC = Land Use Change;
The chart includes emissions for the 6 greenhouse gases
CO2, CH4, N2O, and F-Gases (HFCs, SF6, PFCs) and LUC

Global GHG emissions in 2030 need to be approximately 25 percent and 55 percent lower than in 2017 to put the world on a least-cost pathway to limiting global warming to 2°C and 1.5°C respectively.
Title: Re: Little known greenhouse gases
Post by: ArcticMelt2 on July 07, 2019, 05:05:09 PM
It is also important that at the same time with the continuous growth of greenhouse gas emissions, people in pursuit of comfort very quickly reduce emissions of cooling aerosols (SO2).


With these illogical actions, people are increasingly destabilizing and shaking our fragile climate.

Most still do not realize the consequences of the anthropogenic impact on the planet’s climate, considering that it is miserable.
Title: Re: Little known greenhouse gases
Post by: ArcticMelt2 on July 07, 2019, 05:24:27 PM
So in China, first of all, they are struggling with cooling sprays, spitting on greenhouse gases.

People consider anthropogenic warming nonsense.
Title: Re: Little known greenhouse gases
Post by: gerontocrat on January 21, 2020, 02:07:01 PM
Count the ways humanity pollutes our atmosphere
Study finds shock rise in levels of potent greenhouse gas
Scientists had expected fall in levels of HFC-23 after India and China said they had halted emissions
HFC-23 (also known as CHF3, fluoroform or trifluoromethane) is a potent greenhouse gas (GHG), with a global warming potential (GWP) of 14 800 for a 100-year time horizon. It is an unavoidable by-product of HCFC-22 (CHClF2, chlorodifluoromethane) production. HCFC-22, an ozone depleting substance (ODS), is used extensively in commercial refrigeration and air conditioning, in the extruded polystyrene (XPS) foam industries (dispersive applications) and also as a feedstock in fluoropolymer manufacture (a non-dispersive use). Aside from small markets in specialty uses, HFC-23 has historically been considered a waste gas that was, and often still is, simply vented to the atmosphere. Efforts have been made in the past two decades to reduce HFC-23 emissions,
Title: Re: Little known greenhouse gases
Post by: kassy on January 21, 2020, 02:58:31 PM
This link is about the same;

This gas has very few industrial applications. However, levels have been soaring because it is vented to the atmosphere during the production of another chemical widely used in cooling systems in developing countries.

Looks like we ´forgot´some standards since the market is clearly not interested in preventing the waste of venting. In fact i often wonder about how little some people involved in this seem to care about pollutants they are dumping (mainly related to the Chemical industry).
Title: Re: Little known greenhouse gases
Post by: kassy on June 19, 2020, 03:47:55 PM
A Switch in How Hospitals Use Anesthesia Could Have Huge Climate Benefits


The problem is that the most common inhalants used for general anaesthesia are nitrous oxide (or laughing gas) and desflurane. Both are greenhouse gases that can stay in the atmosphere for decades and wreak havoc on the climate (they also damage the ozone layer to boot). In fact, nitrous oxide is nearly 300 times more potent than carbon dioxide in terms of planet-warming potential. Desflurane’s potential is up to 3,700 worse than carbon dioxide, making it one of the most intense greenhouse gases in use. The process of using these drugs is also wasteful. When doctors administer these gases, patients inhale just 5% of them. The rest of gets sucked into a ventilation system, and then floats up into the atmosphere.

In 2009, more than one million hip and knee replacement procedures – which are usually done with general anaesthesia – were performed in the US alone. The authors calculated that if all of these were done under general anaesthetic, that would be the equivalent of nearly 247,000 lbs (112,000 kilograms) of desflurane and nearly 20,000 lbs (9,000 kilograms) of nitrous oxide released into the atmosphere. That’s equivalent to burning more than 3.2 million pounds of coal.


 in 2019, the hospital chose regional anaesthesia in those procedures whenever they could. Out of the 10,485 hip and knee replacements it carried out that year, hospital doctors gave just 4% of patients general anaesthetic. Doing so, the study found, saved the greenhouse gas equivalent of burning nearly 27,000 lbs (12,246 kilograms) of coal.
Title: Re: Little known greenhouse gases
Post by: Tom_Mazanec on June 23, 2020, 02:16:36 AM
Interesting, kassy, but I don't know about that "huge" in the headline. What amount of the CO2 would this measure reduce? 1 ppm? Every little bit helps, but the headline is deceptive.
Title: Re: Little known greenhouse gases
Post by: kassy on June 23, 2020, 01:23:11 PM
´Huge climate benefits´

This research shows that for many types of operations we can just not use the really polluting general anesthesia. The numbers are for US and then from 1 hospital but they can be scaled up to worldwide. And we can do that now without loss of quality of care (while we can´t stop building etc).

With our small remaining budget we need all the low hanging fruit we can get our hands on.