CIA World Factbook
https://www.cia.gov/library/publications/the-world-factbook/index.html
The CIA World Factbook is an excellent source of general data on all countries in the world. There are data on numerous subjects including demographics, social/political indicators, economics/political economy and geography.
Paul Hensel's International Environmental Data Page
http://www.paulhensel.org/dataenv.html
This site, which is hosted by Dr. Paul Hensel, contains links to data on a variety of environmental topics such as fisheries, energy, water disputes, and agricultural production.
United Nations Food and Agriculture Organization (FAO) Statistics
http://www.fao.org/statistics/en/
The FAO is a UN organization that is ostensibly devoted to alleviating world hunger. The FAO's collection of statistics and databases covers a variety of topics, such as water, agricultural production, and agricultural consumption. The geographic and time coverage vary by topic and database. Users can query the databases to create extracts of data of interest or can download the data in bulk format.
World Bank Environment
http://www.worldbank.org/en/topic/environment
This World Bank site contains links to various resources, including collections of environmental data and statistics. The Bank also produces more specialized data collections, such as the Wealth of Nations data on the sustainability of countries' growth trajectories and the Adjusted Net Savings data that incorporate the effects of environmental depletion. See also the environmental data section within the Bank's data collections.
World Development Indicators (World Bank)
https://datacatalog.worldbank.org/dataset/world-development-indicators
The World Development Indicators provide convenient access to hundreds indicators on over 200 countries and territories. Data are available annually from 1960 forward, with variation across countries and indicators. The database is part of the Bank's Data Catalog of statistical databases and other data collections. The WDI is also accessible via Databases at Emory and on CD-ROM in the Data Center. There are also multiples tools available for importing WDI data directly into programs such as R and Stata.