By Karl-Erik Stromsta in New York
Monday, April 14 2014
Updated: Tuesday, August 19 2014
The IPCC’s third volume of its fifth assessment report focuses on how human-produced greenhouse gas emissions have changed over recent decades and discusses how future increases in global warming might be avoided. More than 400 authors and almost 900 reviewers from around the globe worked on the report.
“The high speed mitigation train needs to leave the station very soon, and all of global society needs to get on board,” said IPCC chair Rajendra Pachauri at the launch of the report in Berlin.
The assessment, which is endorsed by governments, is meant as the main scientific guide for nations as they prepare for the COP21 climate change conference in Paris in December 2015.
Governments have already promised to limit temperature rises to a maximum 2 degrees Celsius above pre-industrial times to avert more heatwaves, floods, droughts and rising sea levels, which the IPCC says are linked to man-made warming.
Such levels are still attainable, it says, but policies in place so far have put the world on target for a temperature rise of up to 4.8C by 2100. Temperatures have already risen by about 0.8C since the Industrial Revolution of the 18th and 19th centuries.
IPCC scenarios showed world greenhouse gases emissions, mainly from burning fossil fuels, would need to peak soon, tumble by between 40% and 70% from 2010 levels by 2050, and then to almost zero by 2100, to keep temperature rises to below 2C.
“The message of this report is clear. Greenhouse emissions have accelerated in recent years due to human activity,” said UK energy secretary Ed Davey. “We need a large-scale change to our global energy system if we are to limit the effects of climate change. The longer we leave it, the more difficult and costly it will be."
Maf Smith, industry body RenewableUK’s deputy chief executive, added: “When it comes to taking practical action against carbon emissions, the most useful tool in the kit is wind energy. It’s the most developed renewable technology we have, providing more than half the low-carbon electricity we generate in the UK."
Reacting to the report, Germany’s environment minister Barbara Hendricks and research minister Johanna Wanka jointly called for a global Energiewende – or energy transition towards renewable energies and resource efficiency.
Hendricks says the international community this year and next needs to determine the course for a binding, global post-2020 accord. “Europe needs to forge ahead here. Therefore, we want to determine an EU-wide climate target of at least 40% by 2030 as fast as possible,” Hendricks says.
The IPCC says in order to achieve such temperature reductions, energy demand will need to be met through a combination of technologies such as renewables, nuclear power and using carbon capture and storage on much of the remaining fossil fuel use.
It says that natural gas, which emits fewer greenhouse emissions, could get a boost up until 2050 and become a key bridging fuel in moving energy production away from coal and oil.
A major unknown is the capacity for artificial greenhouse gas removal, which allows more flexibility in the amount of fossil fuel emissions. However, there is great uncertainty around the potential size of such a removal and its likely side-effects.
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