[11] Arnika, founded on 29 September 2001, by environmentalists Jindřich Petrlík, Martin Skalský, Vlastimil Karlík, and Lenka Mašková, originated after their departure from the Czech NGO Děti Země.

[19] Arnika led the Toxics-Free Future campaign between 2001-2004, contributing to the establishment of a Pollutant Release and Transfer Register (PRTR) in the Czech Republic and the ratification of the Stockholm Convention.

[22][23] Since its establishment in 2001, Arnika has consistently opposed the construction of new dams on the Elbe near Děčín, emphasizing the protection of ecosystems in Natura 2000 species sites and the preservation of migratory fish, such as salmon.

In 2005, the organization filed a complaint with the European Commission, leading to a warning about the Czech government's insufficient designation of Special Protection Areas (SPA).

[7] Arnika raised concern over Prague potentially losing its UNESCO World Heritage status and pushed for restricting the height of buildings planned by developers on the Pankrác Plain in 2008.

[30] Jan Hodovský, author of the Environmental Impact Assessment (EIA) documentation on dams on the Elbe in 2011, made similar claims about Arnika's funding from German railways.