tiistai 23. syyskuuta 2014

Global CO2 emissions record high

The latest annual update shows that the global CO2 emissions are record high. This is the conclusion of a paper by the Global Carbon Project currently in discussion status in the open access journal Earth System ScienceData. The current estimates for the emissions are joint effort between 49 institutes and the study is led by Prof Le Quéré, Director of the Tyndall Centre at the University of East Anglia.

To come up with science based estimates is not trivial task. The emissions come from several sectors and each one of them has different challenges. However, these type of data and its annual updates are extremely valuable for not only to scientists but also decision makers, journalists and to general public which should use this information together with other environmental data such as temperature, precipitation or ice cover.

The total global emissions during 2013 were about 40 billion tonnes. This amount is mainly due to burning of fossil fuels and cement production. Minor fraction comes from the deforestation. In addition, there are several other sources, but their combined role remains smaller.

The record high emissions have also resulted to record high atmospheric concentrations. The concentration of carbon dioxide in the atmosphere has increased from about 277 parts per million (ppm) during year 1750, the beginning of industrialization, to 395 ppm in 2013. Daily averages reached 400 ppm for the first time at Mauna Loa station in May 2013.

The increasing emissions have also important consequences for the target to limit the increase of the global temperature. It has been estimated that the cumulative emissions of CO2 should not exceed 1200 billion tonnes in order to keep the temperature rise within 2 degree limit. If the emissions continue with the current rate, this limit will be reached in just 30 years, as concluded by the Global Carbon Project.

The global CO2 emissions were dominated by emissions from China (28 %), the USA (14 %), the EU (28 member states; 10 %), and India (7 %). Interestingly, the EU was the only one with decreasing emissions, while the growth of emissions from the other three increased by 3-5% from the year before. Perhaps this is the moment for Europe to start the new growth without increase in carbon emissions.