Washington, D.C. · April 10, 1941

On April 9, 1941, a full year after Operation Weser­uebung had brought Den­mark and Nor­way into Nazi Ger­many’s orbit, the Dan­ish minis­ter in Wash­ing­ton, D.C., Hen­rik Kauff­mann, signed a treaty with the United States, autho­rizing the U.S. to pro­tect the remote Dan­ish colony of Green­land “against attack by a non-Amer­i­can power” and to con­struct mili­tary sta­tions on the is­land for that pur­pose. The Dan­ish en­voy, notable for re­fusing to recog­nize the Nazi occu­pa­tion of his coun­try, was sup­ported in his move by Dan­ish diplo­mats in the U.S. and by autho­rities in Green­land, who were keenly aware of the diffi­culties Den­mark faced in gov­erning the is­land after the out­break of war. By signing the treaty “in the name of the King,” Kauff­mann was in clear vio­la­tion of his diplo­ma­tic powers. Indeed, the treaty, while affirming Greenland’s loyalty to the mother country, was disavowed by author­ities in Copen­hagen because it allowed the U.S. to establish bases on Danish territory.

On this date in 1941, a day after the signing cere­mony, Pre­si­dent Frank­lin D. Roose­velt played his trump card by declaring Green­land to be part of the West­ern Hemi­sphere. This decla­ra­tion brought Green­land under the pro­vi­sions of the Mon­roe Doc­trine, which U.S. presi­dents had used to oppose Euro­pean inter­fer­ence in the Americas for over a century. The inclu­sion of Green­land into what the U.S. con­sid­ered its ex­clu­sive play­ground was all the more im­por­tant after Ger­many had made recon­nais­sance flights over Green­land, causing concern in Wash­ing­ton circles that Adolf Hitler might try to estab­lish bases on the is­land for future use against the U.S. Green­land’s occu­pa­tion by Amer­i­can forces on the same day as the announce­ment was followed two months later by the occu­pa­tion of the stra­te­gically located Dan­ish depend­ency of Ice­land, where U.S. Marines sup­ple­mented and even­tu­ally replaced Brit­ish and Cana­dian ser­vice mem­bers who had been sta­tioned there since May 10, 1940.

The occu­pa­tion of Green­land and Ice­land brought the Roose­velt ad­min­is­tra­tion closer to sup­porting Great Brit­ain in its Battle of the Atlan­tic. Hence­forth, U.S. Navy ves­sels ex­tended their con­voy patrols to these two ter­ri­tories, both lying along the sea lanes linking the U.S. to its future ally against Nazi Germany.

Greenland’s Role in the “Weather War”

Captured German weathermen, Greenland, October 4, 1944North-East Greenland Sledge Patrol HQ

Left: The Germans set up three sec­ret weather sta­tions on Green­land’s east­ern shore to pro­vide them with ad­vance weather in­for­ma­tion for the dual pur­pose of assisting their sub­marine, sur­face, and air cam­paign against Allied mer­chant shipping in the North At­lan­tic and pre­dicting as much as 72 hours in ad­vance the weather situ­a­tion in the Euro­pean thea­ter. (The Ger­mans briefly had one re­mote weather sta­tion set up on the north­ern tip of Lab­ra­dor, New­found­land, on the North Amer­i­can con­ti­nent.) The Allies used weather data gathered from their own weather sta­tions in Green­land to plan the invasion of Normandy, France. As poor as this photo is, it depicts mem­bers of the Ger­man Edel­weiss II weather sta­tion being taken prisoner three days after their landing by a team of 200 U.S. soldiers, October 4, 1944.

Right: To show the Allies their willing­ness to fight the Ger­mans in the Arctic deso­la­tion of their home­land, a small band of Danes, Nor­we­gians, and native Green­landers came together as the North-East Green­land Sledge Patrol in the sum­mer of 1941. The patrol’s acti­vi­ties were to lo­cate and eli­mi­nate Ger­man radio and weather sta­tions. In March 1943 a dog-team patrol dis­covered the Ger­man weather reporting sta­tion Holz­auge at Hansa Bay on the north­east coast, where it had been oper­a­ting since August 1942. In May 1943 U.S. air­craft from Ice­land bombed the sta­tion. This photo shows the head­quarters of the Sledge Patrol in the Northern District at Dane­borg/­Sandod­den, Green­land. Note the Danish flag atop the building.

Various Newsreel Clips from 1944, the First Showing the Destruction of German Radio and Weather Stations in Greenland