A controversial tribunal decision that some company practices can discriminate against employees with strongly held views on climate change will be challenged in the courts.

Senior executive Tim Nicholson claimed he was unfairly dismissed by a property investment company because his views on the environment conflicted with other managers' "contempt for the need to cut carbon emissions".

In the first case of its kind, an employment tribunal decided that Nicholson, 41, had views amounting to a "philosophical belief in climate change", allowing him the same legal protection against discrimination as religious beliefs.

Nicholson, the former head of sustainability at Newcastle-based Grainger plc, says he was dismissed after disagreeing with practices including an instance where an IT worker was flown from London to Ireland to collect his BlackBerry, and another where Nicholson's attempts to obtain data to develop a carbon management strategy were blocked.

Despite having written policies on the environment, Grainger executives attended meetings in "some of the most highly polluting cars on the road", Nicholson claimed.

"[My belief] affects how I live my life including my choice of home, how I travel, what I buy, what I eat and drink, what I do with my waste, and my hopes and fears," he said. "For example, I no longer travel by plane, I have eco-renovated my home, I compost my food waste and encourage others to reduce their carbon emissions."

Judge David Sneath said at the employment tribunal: "[Nicholson] has certain views about climate change and acts upon those views in the way in which he leads his life. In my judgment his belief goes beyond a mere opinion."

The decision, which is being challenged by the company, comes two years after the law on religious discrimination was changed so that beliefs no longer had to be "similar" to religious faith to receive protection in the workplace.

Under the new law "philosophical belief" is protected by the law alongside religious belief if it passes a legal test requiring it to be cogent, serious and "worthy of respect in a democratic society".

The case has attracted criticism from some, however, who argue that the removal of the requirement that beliefs are "similar" to religious faith will create a potential minefield for employers.

Caroline Doran, employment partner at London solicitors Sprecher Grier Halberstam, said: "The removal of the word similar has [also] led to a range of employment litigation to determine whether patriotism or loyalty to a flag or support for the British National party are covered as suitable beliefs.

"This … may create an abundance of litigation in the future as the tribunals will have to weigh an individual's belief against the yardstick of current popular thinking."

Nicholson's lawyer said that the case reflected a necessary clarification of the law that would affect large numbers of employees.

"This is a case that will clarify the law for the ever-increasing numbers of people who take a philosophical stance on the environment and climate change, and who lead their lives according to those principles", said Shah Qureshi, head of employment law at solicitors Bindmans.

"These are often deeply held views based on the premise that without change humanity will suffer … people should be able to express such views without fear of retribution or discrimination."