Australian study: Countries must lower carbon emissions soon

An Australian study from the University of Melbourne scientists, along with other scientists around the world, conducted a comprehensive review of 193 emission scenarios from existing scientific literature before concluding that decisive action in this decade will be needed, if the world is to stay below a global warming of 2 degrees for the coming century. The study was published in Nature Climate Change on October 24, 2011. These scientists say the world must lower its carbon emissions very soon.

It is no surprise these Australian scientists are expressing a sense of urgency. Australia is thought to be one of the places in the world most vulnerable to the effects of global warming projected for the next 50 to 100 years. That’s in part because Australia already has a lot of desert. It has variable rainfall from year to year. There are already pressures on water supply in Australia. Plus Australia has a high fire risk that is susceptible to changes in temperature and climate.

United Nations conferences in Copenhagen in 2009 and Cancun 2010 set goals of 44 billion tons of carbon-dioxide-equivalent emissions (GtCO2eq) by 2020. A 2010 United Nations Emissions Gap report – which had summarized all comparable emissions pledges by industrialized and developing countries – found 2020 emissions would still rise well beyond 50 GtCO2eq. However, the Australian scientists suggest a goal of 44 GtCO2eq is a feasible milestone if countries honor the higher end of their pledges.

According to Malte Meinshausen of the University of Melbourne’s School of Earth Sciences, a senior author on the study, the world is currently at 48 GtCO2eq. Thus this research agrees with the previous UN study in suggesting a need to reverse the growing emission trend in this decade.

The study analyzed feasible emissions scenarios, which included a mix of mitigation actions ranging from energy efficiency to carbon-free technologies such as solar photovoltaic, wind and biomass. Using a risk-based climate model developed by Dr. Meinshausen, an international team of scientists led by Joeri Rogelj from ETH Zurich, Switzerland, analyzed how global greenhouse gas emissions in 2020 can be managed with a long-term 2-degree target.

By analyzing the emissions scenarios in the climate model, researchers were able to generate a probabilistic projection of CO2 concentration in the atmosphere and global temperature for the next 100 years. The study also determined which scenarios provided the best possible chance of reaching the global target of 2 degrees and moving to a zero-carbon economy in the latter half of the century. Meinshausen said:

As long as we keep emitting carbon dioxide, the climate will continue to warm. There is no way around a zero-carbon economy sooner or later if we want to stay below 2 degrees.

In Australia, the Federal Government recently announced its emission trading system to reduce its emissions by 5% to 25% below 2000 levels. Targeting the 500 top polluters is the cornerstone to the Australian policy to achieve its 5% target. Meinshausen said:

Our study confirms that only by moving to the more ambitious end of the pledges, 25% in the case of Australia, the world would be getting closer to being on track to the 44 GtCO2eq, 2 degree milestone.

If the international community is serious about avoiding dangerous climate change, countries seem ill-advised by continuing to increase emissions, which they have done so in the last 10 years, which ultimately will lead to disastrous consequences later on.

We can anticipate Australia will be one of the countries hardest hit by climate change due to recent years of droughts and floods. This is consistent with projections that we are going to expect more of these kinds of extreme conditions in the coming decades.

By our calculations, the world needs to do more this decade, as otherwise the 2-degree target to avert serious effects of climate change, is slipping out of reach.

Bottom line: Australian scientists at University of Melbourne, and scientists from around the world, published results of a study October 24 in Nature Climate Change, indicating an urgent need for countries to lower their carbon emissions soon, if the world is to stay below a global warming of 2 degrees for the coming century. Their study was based on a comprehensive review of 193 emission scenarios from existing scientific literature.

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November 3, 2011

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