After finishing school in 1973 Griefahn went to the universities of Göttingen and Hamburg to study mathematics and social sciences.

Additionally she helped found new offices in Austria, Belgium, Switzerland, Latin America and the former Soviet Union.

In 1990 Minister-President Gerhard Schröder of Lower Saxony named her as the Minister for the Environment, where she started special programs to support renewable energy systems (wind power, solar, biomass) in order to stop the use of nuclear power (more see "Public Offices").

Her plans, which finally became reality in 2011 (after the Fukushima nuclear accident), were blocked by directives of the Federal Ministry of the Environment, headed by Klaus Töpfer (1990–1994) and Angela Merkel (1994–1998).

Her commitment contributed to the fact that the plans to phase out nuclear power[broken anchor] became a reality between 1998 and 2005, when a coalition of the Social Democratic Party and the Greens led the Federal Government (First ans Second Schröder cabinet).

Furthermore, she was a member of the Committee on Foreign Affairs (Auswärtiger Ausschuss) and of the Sub-committees on Cultural Policy Abroad and New Media.

In 2005 Griefahn was elected chair of the bilateral committee on cultural diversity, which was appointed by the Bundestag and the French Assemblée Nationale.

In addition to her committee assignments, Griefahn served as deputy chair of the German-French Parliamentary Friendship Group from 2006 until 2009.

From 2015 until 2016, Griefahn served on a government-appointed commission tasked with recommending how to safeguard the funding of fulfilling Germany's exit from nuclear energy, under the leadership of co-chairs Ole von Beust, Matthias Platzeck and Jürgen Trittin.