Dr. Newman of NASA interviewed by Rajendra Shende, TERRE on Status of Ozone Layer

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Dr. Paul Newman, Chief Scientist for Atmospheric Sciences Earth Sciences Division of NASA’s Goddard Space Flight Center, USA answered in cyber space key questions of Rajendra Shende, Chairman TERRE.

Occasion was the release of The Assessment for Decision-Makers, a summary document of the Scientific Assessment of Ozone Depletion 2014, being prepared jointly by UNEP and WMO on 10th Sept 2014. The background of the interview was  summary of Key Findings published by UNEP on the same day 

Key findings:

Actions taken under the Montreal Protocol on Substances that Deplete the Ozone Layer are enabling the return of the ozone layer to benchmark 1980 levels.

  • Under full compliance with the Montreal Protocol, the ozone layer is expected to recover to 1980-benchmark levels- the time before significant ozone layer depletion- before the middle of the century in mid-latitudes and the Arctic, and somewhat later in the Antarctic.
  • The Montreal Protocol and associated agreements have led to decreases in the atmospheric abundance of gases, such as CFCs (chlorofluorocarbons) and halons, once used in products such as refrigerators, spray cans, insulation foam and fire suppression.
  • Total column ozone declined over most of the globe during the 1980s and early 1990s. It has remained relatively unchanged since 2000, but there are recent indications of its future recovery.
  • The Antarctic ozone hole continues to occur each spring and it is expected to continue occurring for the better part of this century given that ozone-depleting substances persist in the atmosphere, even though their emissions have ceased.
  • The Arctic stratosphere in winter/spring 2011 was particularly cold, which led to large ozone depletion as expected under these conditions.

The climate benefits of the Montreal Protocol could be significantly offset by projected emissions of HFCs (hydrofluorocarbons) used to replace ozone-depleting substances.

  • The Montreal Protocol has made large contributions toward reducing global greenhouse gas emissions. In 1987, ozone-depleting substances contributed about 10 gigatonnes CO2-equivalent emissions per year. The Montreal Protocol has now reduced these emissions by more than 90 per cent. This decrease is about five times larger than the annual emissions reduction target for the first commitment period (2008-2012) of the Kyoto Protocol on climate change.
  • Hydrofluorocarbons (HFCs) do not harm the ozone layer but many of them are potent greenhouse gases. They currently contribute about 0.5 gigatonnes of CO2-equivalent emissions per year. These emissions are growing at a rate of about 7 per cent per year. Left unabated, they can be expected to contribute very significantly to climate change in the next decades.
  • Replacements of the current mix of high-GWP HFCs with alternative compounds with low GWPs or not-in-kind technologies would limit this potential problem.

The annual Antarctic ozone hole has caused significant changes in Southern Hemisphere surface climate in the summer.

  • Ozone depletion has contributed to cooling of the lower stratosphere and this is very likely the dominant cause of observed changes in Southern Hemisphere summertime circulation over recent decades, with associated impacts on surface temperature, precipitation, and the oceans.
  • In the Northern Hemisphere, where the ozone depletion is smaller, there is no strong link between stratospheric ozone depletion and tropospheric climate.

CO2, Nitrous Oxide and Methane will have an increasing influence on the ozone layer

  • What happens to the ozone layer in the second half of the 21st century will largely depend on concentrations of CO2, methane and nitrous oxide – the three main long-lived greenhouse gases in the atmosphere. Overall, CO2 and methane tend to increase global ozone levels. By contrast, nitrous oxide, a by-product of food production, is both a powerful greenhouse gas and an ozone depleting gas, and is likely to become more important in future ozone depletion.

INTERVIEW

1. We have been hearing the news for pretty long time that Ozone layer is being recovered. So what is new observation being made in 2014 assessment launched today?

For many years now, scientists have been saying that ozone depletion is not getting any worse. With this assessment, we are now seeing the first signs that ozone is on the upswing. In particular, if you look at observations in the Northern mid-latitudes at an altitude of 42 km, we see that ozone has increased over the 2000 to 2013 period. We cannot definitively say that the Antarctic ozone hole is getting better, nor can we say that global ozone is on the upswing, but there are hints that ozone is starting to improve.

2. HFCs are introduced, as ozone-friendly substitutes for CFCs and HCFCs. HFCs are global warming gases. Hence Ozone issue is addressed by creating climate problem. How then we can say that MP has benefitted the actions to safeguard the climate?

CFCs, HCFCs, and many HFCs are powerful greenhouse gases. The Montreal Protocol’s regulation of CFC and HCFC production and consumption not only helps the ozone layer; it also helps reduce a large climate impact. However, HFCs are not regulated under the Montreal Protocol, and these HFCs are being used as replacement compounds for the CFCs and HCFCs. Levels of HFCs are still low, but they are growing at a rate of about 7% per year. In 2010, the decrease of annual ODS emissions under the Montreal Protocol was about 10 gigatonnes of avoided CO2-equivalent emissions per year. By 2050, we estimate that HFC emissions of up to 8.8 gigatonnes CO2-equivalent per year. The HFC CO2-equivalent emissions are projected to grow to the levels of CFC CO2-equivalent emissions that the Montreal Protocol eliminated.

 3. The banks of CFCs, HCFCs and HFCs are likely to impact the climate severely. Destruction of banks is costly and not really being implemented. Does that mean that governments have blatantly ignored the Scientists’ warning? Or Scientists have not been quick enough and strong enough to warn?

This is more a political question and scientists cannot prescribe to the governments what they should do. Advocating particular policy action is outside the scope of Science Assessment Panel. However, destroying banks of ODSs and eliminating all future production of HCFCs, CCl4, and QPS CH3Br could accelerate ozone recovery by about 11 years, if implemented.

4. Does the assessment give categorical message that humanity has succeeded in averting the ‘ ozone depletion’ tragedy? Or as a scientist you would like to say that with a condition? Which?

If CFCs and Halons had continued to grow at a modest 3% per year, by the year 2065, two-thirds of the ozone layer would have been destroyed. This would have disastrously reduced crop yields and would have had a huge impact on human health. The Montreal Protocol prevented this!

END

 

 

Dr. Newman of NASA interviewed by Rajendra Shende, TERRE

 

Dr. Paul Newman, Chief Scientist for Atmospheric Sciences
Earth Sciences Division of NASA’s Goddard Space Flight Center, USA answered in cyber space key questions of Rajendra Shende, Chairman TERRE. Occasion was the release of The Assessment for Decision-Makers, a summary document of the Scientific Assessment of Ozone Depletion 2014, being prepared jointly by UNEP and WMO on 10th Sept 2014.

 

The background of the interview was following summary of Key Findings.

Key findings:

Actions taken under the Montreal Protocol on Substances that Deplete the Ozone Layer are enabling the return of the ozone layer to benchmark 1980 levels.

  • Under full compliance with the Montreal Protocol, the ozone layer is expected to recover to 1980-benchmark levels- the time before significant ozone layer depletion- before the middle of the century in mid-latitudes and the Arctic, and somewhat later in the Antarctic.
  • The Montreal Protocol and associated agreements have led to decreases in the atmospheric abundance of gases, such as CFCs (chlorofluorocarbons) and halons, once used in products such as refrigerators, spray cans, insulation foam and fire suppression.
  • Total column ozone declined over most of the globe during the 1980s and early 1990s. It has remained relatively unchanged since 2000, but there are recent indications of its future recovery.
  • The Antarctic ozone hole continues to occur each spring and it is expected to continue occurring for the better part of this century given that ozone-depleting substances persist in the atmosphere, even though their emissions have ceased.
  • The Arctic stratosphere in winter/spring 2011 was particularly cold, which led to large ozone depletion as expected under these conditions.

The climate benefits of the Montreal Protocol could be significantly offset by projected emissions of HFCs (hydrofluorocarbons) used to replace ozone-depleting substances.

  • The Montreal Protocol has made large contributions toward reducing global greenhouse gas emissions. In 1987, ozone-depleting substances contributed about 10 gigatonnes CO2-equivalent emissions per year. The Montreal Protocol has now reduced these emissions by more than 90 per cent. This decrease is about five times larger than the annual emissions reduction target for the first commitment period (2008-2012) of the Kyoto Protocol on climate change.
  • Hydrofluorocarbons (HFCs) do not harm the ozone layer but many of them are potent greenhouse gases. They currently contribute about 0.5 gigatonnes of CO2-equivalent emissions per year. These emissions are growing at a rate of about 7 per cent per year. Left unabated, they can be expected to contribute very significantly to climate change in the next decades.
  • Replacements of the current mix of high-GWP HFCs with alternative compounds with low GWPs or not-in-kind technologies would limit this potential problem.

The annual Antarctic ozone hole has caused significant changes in Southern Hemisphere surface climate in the summer.

  • Ozone depletion has contributed to cooling of the lower stratosphere and this is very likely the dominant cause of observed changes in Southern Hemisphere summertime circulation over recent decades, with associated impacts on surface temperature, precipitation, and the oceans.
  • In the Northern Hemisphere, where the ozone depletion is smaller, there is no strong link between stratospheric ozone depletion and tropospheric climate.

CO2, Nitrous Oxide and Methane will have an increasing influence on the ozone layer

  • What happens to the ozone layer in the second half of the 21st century will largely depend on concentrations of CO2, methane and nitrous oxide – the three main long-lived greenhouse gases in the atmosphere. Overall, CO2 and methane tend to increase global ozone levels. By contrast, nitrous oxide, a by-product of food production, is both a powerful greenhouse gas and an ozone depleting gas, and is likely to become more important in future ozone depletion.

INTERVIEW

 

1. We have been hearing the news for pretty long time that Ozone layer is being recovered. So what is new observation being made in 2014 assessment launched today?

 

 

For many years now, scientists have been saying that ozone depletion is not getting any worse. With this assessment, we are now seeing the first signs that ozone is on the upswing. In particular, if you look at observations in the Northern mid-latitudes at an altitude of 42 km, we see that ozone has increased over the 2000 to 2013 period. We cannot definitively say that the Antarctic ozone hole is getting better, nor can we say that global ozone is on the upswing, but there are hints that ozone is starting to improve.

 

2. HFCs are introduced, as ozone-friendly substitutes for CFCs and HCFCs. HFCs are global warming gases. Hence Ozone issue is addressed by creating climate problem. How then we can say that MP has benefitted the actions to safeguard the climate?

 

CFCs, HCFCs, and many HFCs are powerful greenhouse gases. The Montreal Protocol’s regulation of CFC and HCFC production and consumption not only helps the ozone layer; it also helps reduce a large climate impact. However, HFCs are not regulated under the Montreal Protocol, and these HFCs are being used as replacement compounds for the CFCs and HCFCs. Levels of HFCs are still low, but they are growing at a rate of about 7% per year. In 2010, the decrease of annual ODS emissions under the Montreal Protocol was about 10 gigatonnes of avoided CO2-equivalent emissions per year. By 2050, we estimate that HFC emissions of up to 8.8 gigatonnes CO2-equivalent per year. The HFC CO2-equivalent emissions are projected to grow to the levels of CFC CO2-equivalent emissions that the Montreal Protocol eliminated.

 

 

3. The banks of CFCs, HCFCs and HFCs are likely to impact the climate severely. Destruction of banks is costly and not really being implemented. Does that mean that governments have blatantly ignored the Scientists’ warning? Or Scientists have not been quick enough and strong enough to warn?

 

This is more a political question and scientists cannot prescribe to the governments what they should do. Advocating particular policy action is outside the scope of Science Assessment Panel. However, destroying banks of ODSs and eliminating all future production of HCFCs, CCl4, and QPS CH3Br could accelerate ozone recovery by about 11 years, if implemented.

 

 

4. Does the assessment give categorical message that humanity has succeeded in averting the ‘ ozone depletion’ tragedy? Or as a scientist you would like to say that with a condition? Which?

 

If CFCs and Halons had continued to grow at a modest 3% per year, by the year 2065, two-thirds of the ozone layer would have been destroyed. This would have disastrously reduced crop yields and would have had a huge impact on human health. The Montreal Protocol prevented this!

END

 

 

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