I searched for data on global greenhouse gas emissions by country and was disappointed with what I found. Data in AR5 WG3 are from 2010. The Wikipedia site’s data are from 2010. It says they are from World Resources Institute (WRI), but WRI just gets their data from the UNFCCC. By the way, WRI’s new Climate Data Explore (CAIT), provides some interesting graphic output. However, it uses 2012 data.
Under the United Nations’s Framework Convention for Climate Change (UNFCCC) treaty (which was ratified by the US Senate), Annex I countries to the treaty (the more industrialized nations) are required to report their annual emissions of greenhouse gasses. The UNFCCC established and maintains the technical guidelines for doing this, and compiles the data. However, this process is disappointingly slow. While a note on the homepage reports that the data have been updated with 2013 numbers, all the downloads on the Annex I time-series data page only extend only to 2012. The same goes for the country GHG profiles (which are very useful). The only place I could find 2013 data on the UNFCCC site was in the national reports, which are here. Apparently the 2013 have not been organized by UNFCCC, or at least, I could not find it on their website.
UNFCCC exports data to numerous sites and that list is available here. It includes the USEPA, but the most current data on the USEPA site is from 2012. It also includes the Netherlands Environmental Assessment Agency. The best report on that site was the Trends in Global CO2 Emissions. This is a 2014 report that includes 2013 data. It notes in the report that the data are somewhat preliminary, however they have good confidence in the overall accuracy. If you are concerned about the high accuracy numbers for an individual country, you will have difficulty finding data that are newer than 2012.
The Carbon Dioxide Information Analysis Center at Oak Ridge National Lab (US Department of Energy), also estimates CO2 emissions. The estimates for 2011-2013 are preliminary. It is these estimates that are used by the Global Carbon Atlas. It's important to realize that the Atlas is using DOE estimates rather than UNFCCC data.
It’s incredible to me that, in an age when we are so used to having data quickly available, that it would be so difficult to get current data on an issue of this importance.
directs research at the Energy Trans Lab