Global carbon budget 2014

Abstract

Abstract. Accurate assessment of anthropogenic carbon dioxide (CO 2 ) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the development of climate policies, and project future climate change. Here we describe data sets and a methodology to quantify all major components of the global carbon budget, including their uncertainties, based on the combination of a range of data, algorithms, statistics, and model estimates and their interpretation by a broad scientific community. We discuss changes compared to previous estimates, consistency within and among components, alongside methodology and data limitations. CO 2 emissions from fossil Earth Syst. Sci. Data, 7, 47-85, 2015 www.earth-syst-sci-data.net/7/47/2015/ C. Le Quéré et al.: Global carbon budget 2014 49 fuel combustion and cement production (E FF ) are based on energy statistics and cement production data, respectively, while emissions from land-use change (E LUC ), mainly deforestation, are based on combined evidence from land-cover-change data, fire activity associated with deforestation, and models. The global atmospheric CO 2 concentration is measured directly and its rate of growth (G ATM ) is computed from the annual changes in concentration. The mean ocean CO 2 sink (S OCEAN ) is based on observations from the 1990s, while the annual anomalies and trends are estimated with ocean models. The variability in S OCEAN is evaluated with data products based on surveys of ocean CO 2 measurements. The global residual terrestrial CO 2 sink (S LAND ) is estimated by the difference of the other terms of the global carbon budget and compared to results of independent dynamic global vegetation models forced by observed climate, CO 2 , and land-coverchange (some including nitrogen-carbon interactions). We compare the mean land and ocean fluxes and their variability to estimates from three atmospheric inverse methods for three broad latitude bands. All uncertainties are reported as ±1σ , reflecting the current capacity to characterise the annual estimates of each component of the global carbon budget. For the last decade available (2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013), E FF was 8.9 ± 0.4 GtC yr −1 , E LUC 0.9 ± 0.5 GtC yr −1 , G ATM 4.3 ± 0.1 GtC yr −1 , S OCEAN 2.6 ± 0.5 GtC yr −1 , and S LAND 2.9 ± 0.8 GtC yr −1 . For year 2013 alone, E FF grew to 9.9 ± 0.5 GtC yr −1 , 2.3 % above 2012, continuing the growth trend in these emissions, E LUC was 0.9 ± 0.5 GtC yr −1 , G ATM was 5.4 ± 0.2 GtC yr −1 , S OCEAN was 2.9 ± 0.5 GtC yr −1 , and S LAND was 2.5 ± 0.9 GtC yr −1 . G ATM was high in 2013, reflecting a steady increase in E FF and smaller and opposite changes between S OCEAN and S LAND compared to the past decade (2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013). The global atmospheric CO 2 concentration reached 395.31 ± 0.10 ppm averaged over 2013. We estimate that E FF will increase by 2.5 % (1.3-3.5 %) to 10.1 ± 0.6 GtC in 2...

Tracking resource use relative to planetary boundaries in a steady-state framework: A case study of Canada and Spain

“…Since the most recent years are more important given the decreasing relevance of past CO2 emissions due to carbon uptake by ecosystems, our method provides the closest approximation available for cumulative carbon footprints over the entire period. We note that the data obtained from Le Quéré et al (2015) should be considered an underestimate as they do not include CO2 emissions related to international aviation and maritime transport.…”

“…Following Hansen et al (2013), a global emissions reduction pathway to achieve a concentration of 350 ppm CO2 by 2100 was defined with cuts to fossil fuel emissions of 6% per year beginning in 2016, along with ambitious reforestation efforts that capture ~90 Gt C. This emissions pathway yields a global carbon budget of ~700 Gt CO2 between 2013 and 2100. Historical global emissions data were obtained from Boden et al (2013), updated in Le Quéré et al (2015). The static-sink pressure-response function from Kharecha and Hansen (2008) was then applied recursively to the global emissions data and the results were integrated from 1850 to 2100.…”

Thermodynamic Forecasts of the Mediterranean Sea Acidification

“…Oceans play a key role in the mitigation of the increasing atmospheric pCO 2 . Approximately 25% of the total human emissions of CO 2 to the atmosphere is accumulating into the ocean Mikaloff-Fletcher et al, 2006;Le Quéré et al, 2010;Sabine et al, 2011;Le Quéré et al, 2015). Without this buffer capacity of the oceans, the CO 2 content in the atmosphere would have been much higher and global warming and its consequences more dramatic.…”

Assessing carbon dioxide removal through global and regional ocean alkalinization under high and low emission pathways

“…At present the oceans take up about 28 % of anthropogenic CO 2 emitted annually (Le Quéré et al, 2015). As CO 2 is taken up by the ocean it changes its chemical equilibrium, reducing the carbonate ion concentration and decreasing pH, collectively known as ocean acidification.…”