(Adds Greenpeace reaction, details)
By Alister Doyle and Terje Solsvik
OSLO, Jan 4 (Reuters) - An Oslo court approved Norway's plans for more oil exploration in the Arctic on Thursday, dismissing a lawsuit by environmentalists who had said it violated people's right to a healthy environment.
The case, brought by Greenpeace and the Nature and Youth Group, had argued that a 2015 oil licensing round in the Arctic that gave awards to Statoil, Chevron and others violated Norway's constitution.
But the Oslo district court said the government's oil and gas plans were acceptable. "The state, represented by the Ministry of Petroleum and Energy, is acquitted," it said.
The court ordered the environmental groups to pay the state's legal costs of 580,000 Norwegian crowns ($71,700). Greenpeace said it would decide whether to appeal within the next two weeks.
Norway is Western Europe's largest producer and exporter of oil and gas and plans to keep pumping for decades despite its support for the 2015 Paris climate accord, which aims to end the fossil fuel era this century.
Norway's output from the Arctic remains small, but the region is believed to hold the greatest potential for new discoveries that could gradually replace production from rapidly maturing North Sea and Norwegian Sea fields.
The government's lawyers had argued that the case was a publicity stunt that would cost jobs if it was successful.
"If it was a stunt it would be the most expensive ever," Truls Gulowsen, head of Greenpeace Norway, told Reuters. He said the lawsuit had already cost Greenpeace almost 3 million crowns in legal fees.
Still, he said the case had spurred debate about the risks of Arctic drilling and expressed hopes that it could inspire other lawsuits around the world. About 100 national constitutions, including Norway's, include guarantees of a safe environment.
In its ruling, the court dismissed the environmentalists' arguments that Norway should be responsible for greenhouse gas emissions from oil and gas exported to other nations, rather than just from exploration and drilling off Norway.
The court also said the risks of Arctic drilling were limited.
During the hearing in late 2017, the government said it was inappropriate to invoke the constitution rather than focus on taxes and regulations to control greenhouse gases.
The Norwegian oil industry lobby group welcomed the ruling.
"We've previously said that this is a matter of politics, and politics should be made in parliament, not in the court," said Tommy Hansen, a spokesman for the Norwegian Oil and Gas Association.
Among firms winning stakes in 10 licenses awarded in Norway's 23rd round of awards were Lukoil, ConocoPhillips, Lundin, Aker BP, OMV, Centrica, Idemitsu and others. ($1 = 8.0907 Norwegian crowns) (Additional reporting by Nerijus Adomaitis; Editing by Richard Balmforth)