Reduce greenhouse gases not optional

March 18, 2014

U.N. panel: Reduce greenhouse gases or suffer catastrophic effects

http://ajw.asahi.com/article/sci_tech/environment/AJ201403180044 

THE ASAHI SHIMBUN

Greenhouse gases must be cut 40 to 70 percent within 36 years to prevent cataclysmic environmental changes, according to a U.N. panel’s draft report that urges an immediate shift away from coal-fired power plants.

The draft report by the Working Group III of the Intergovernmental Panel on Climate Change details how the international community should reduce greenhouse gas emissions to curb temperature increases, including the promotion of renewable energy sources.

The IPCC is expected to finalize the draft at a meeting scheduled for April in Germany.

According to the draft obtained by The Asahi Shimbun, growth in both the world’s population and the global economy has accelerated the increase in greenhouse gas emissions since 2000.

The draft report estimates that annual greenhouse gas emissions across the planet were equivalent to 49.5 billion tons of carbon dioxide in 2010, raising the level of greenhouse gases in the atmosphere to around 400 parts per million (ppm)--the highest figure over the past 800,000 years.

To prevent drastic climate changes, the IPCC urges nations to keep temperature increases within 2 degrees compared with levels before the Industrial Revolution in the mid-19th century.

To achieve this goal, the panel advises U.N. member states to take measures to ensure the atmospheric greenhouse gas concentration stays at or below 480 ppm until the end of the century.

It also cites a probability of 50 percent or more that temperature rise will be kept within 2 degrees even if the atmospheric concentration is between 480 ppm and 530 ppm.

According to the draft report, global greenhouse gas emissions must be cut by 40 to 70 percent by 2050 from 2010’s figures to keep temperature increases at or below 2 degrees.

It is unclear when emissions will be able to start declining, but as a countermeasure, the panel emphasizes the necessity of shifting to low-carbon and renewable power generation.

As a first step, nations should replace coal-fired power plants with natural gas-fired ones for the time being, the report said.

They should eventually raise the ratio of low-carbon energy, like nuclear power, and renewable power generation, such as solar power and wind electricity generation, by three to four times from the current 17 percent.

The draft report also calls on countries to introduce more energy-saving technologies for traffic systems, building operations and manufacturing industries.

The U.N. panel’s previous report released seven years ago emphasized nuclear power and anticipated its expanding market share. But the latest draft points out challenges facing the difficult-to-control power generation method, such as safety and dealing with nuclear waste.

The latest draft report evaluates nuclear power as a mature low-carbon technology but says its global share as an electricity-generating method has been falling since 1993.

TH