Researchers also noted the resurgence of a banned gas dubbed CFC-11.
Radio Sputnik discussed this with Oksana Tarasova, Chief of Atmospheric Environment Research at the World Meteorological Organization.
Sputnik: So, how alarming is this recent report?
Oksana Tarasova: The recent report is quite alarming, because, despite the fact that we're all making commitments and the countries are making commitments, we still see the major greenhouse gases are on the rise. The growth rate which we observed in 2017 was average, (mirroring) the growth rate of the last 10 years. So, basically, we do not have any dramatic decrease in the growth rate either. So just for you to put it in the context of the potential for climate change; I would just refer to another report, which was issued by an intergovernmental panel of experts on climate change on 1.5 degree, which says, that we have to decrease our emissions by 45% by 2030. If we look in the atmosphere, we have no signs of any decline in the growth rate, or in concentrations themselves.
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Sputnik: How does the evidence that we've received in this new study differ from that alarming study that we also got news about earlier this year?
Oksana Tarasova: Well, It is not very much different. I mean, we are all telling the same story, and the story is that, basically, out of everything, which is emitted in the atmosphere, about 25% is taken up by the biosphere and 25% taken by the ocean. The rest stays in the atmosphere. For carbon dioxide, the lifetime is indeed very long. So, every molecule counts, which means that CO2 accumulates in the atmosphere and the longer we wait, the more we accumulate. Each molecule is actually playing a role.
It's like a small heater which is flying around you. So, there is no magic wand to remove CO2 from the atmosphere. Basically, it will just stay with our future generations for many, many centuries and it will continue heating the atmosphere.
Sputnik: This study is talking about numerous types of gases. Other than CO2, there is also this gas that was called CFC-11, which is supposedly a banned gas, and it seems that it's resurging. Can you tell us more about this particular gas?
Oksana Tarasova: There is a whole basket of gases which are included in this report, and the major ones are carbon dioxide, methane and nitrous oxide. There is also a set of the smaller gases, which are measured by the Global Observational Network and which are summarized and reported on in this publication. CFC-11 is one of the gases which is a greenhouse gas, but it's also a substance, which is controlled under the Montreux Protocol, because it's also an ozone-depleting substance. What we noticed from the observations and from our network is that, because it is a forbidden substance, it is not produced anymore, so it just escapes from places where it has already been used, like refrigerant and some storage facilities. It is not supposed to be produced.
That is why the level of the concentration of CFC-11 in the atmosphere is declining. But then, we noticed that the rate at which the concentration of CFC-11 in the atmosphere declines doesn't correspond to what should escape from those banks. So, it's declining more slowly than it should be. Then the scientists performed, as we call it, "interesting atmosphere detective work". They put up the atmospheric transport model and started looking at where these (more gradual) rates of decline come from. They manage to identify that the source region is in East Asia. Basically, when these results of research were made public, several countries in East Asia started looking at their reporting. I think, there will be some action taken under the Montreux protocol, because CFC-11 production is forbidden.
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Sputnik: Oksana, could you please tell us a little bit about the sources of these gas emissions?
Oksana Tarasova: Carbon dioxide is a major greenhouse gas. We all understand that the leading greenhouse gas in the atmosphere is water vapour, but we have no control of that. The water vapour is just there, formed by natural thermodynamic processes. So, we're speaking about the anthropogenic-connected greenhouse gasses: the gasses which are linked to human activities. The major one is carbon dioxide. If we look at the contribution of carbon dioxide to the climate, its impact within the last ten years and within the last five years has been about 82% of the [greenhouse gas] contribution to [global] warming. Basically, carbon dioxide is produced by any industry which uses fossil fuel combustion: transport, energy, cement production, and so on and so forth. There is a contribution from land cover change. Here we mean deforestation: when we cut the forests down.
It doesn't produce emissions, but it reduces the uptake of the biosphere. We put this under the category of emissions. That is about 10% of total CO2 emissions. Methane is the second gas, which is the second most important anthropogenic greenhouse gas. It gives us about 17% of the GHG contribution to global warming and about 40% of methane is emitted by natural sources. It is emitted by the wetlands, termites and so on and so forth. Wetlands are the largest source of natural methane. But about 60% of methane comes from anthropogenic sources. Here, we have ruminants, which is (livestock such as) cows, rice agriculture, fossil fuel exploitation, land use and biomass burning. All those sources have an impact, and of course, it would be absolutely wonderful, if we did not emit methane when we do oil and gas drilling, or prevented leakages, or if we all switched to vegetarian diets and didn't use cows, because cows are the main source of methane, the anthropogenic methane.
The third most important gas is nitrous oxide. It provides about 6% of the contribution to the climate warming; 60% of this gas comes from natural sources, like soil, and about 40% is anthropogenic. It means the management of soil by mass burning and the use of fertilizer. Largely, it's the use of fertilizers. When we look at the gradient between two hemispheres, like when we compare the northern hemisphere and southern hemisphere, we can see that difference between them is increasing, because there is massive use of nitrogen fertilizer in the northern hemisphere.
The views and opinions expressed by the speaker do not necessarily reflect those of Sputnik.
