The head of Greenpeace International, Kumi Naidoo, was targeted by intelligence agencies as a potential security threat ahead of a major international summit, leaked documents reveal.

Information about Naidoo, a prominent human rights activist from South Africa, was requested from South African intelligence by South Korea’s National Intelligence Service (NIS) in the runup to a meeting of G20 leaders in Seoul in 2010.

He was linked in the intelligence request with two other South Africans who had been swept up in an anti-terrorist raid in Pakistan but later released and returned to South Africa.

Greenpeace is one of the world’s best-known environmental groups, combining lobbying with high-profile direct action protests. South Korean intelligence may have been concerned about possible disruption at the summit. Told this week of the approach, Naidoo described it as outrageous.

According to a document, marked confidential and written by South African intelligence, the NIS asked its South African counterpart eight months before the summit “to indicate any possible security threat against the president of South Africa during the G20 summit to be held in South Korea from 11-12 November 2010”.

The document added: “Specific security assessments were requested on the following SA nationals: the Director of Green Peace [sic], Mr Kim Naidoo; Mr Feerzoz Abubaker Ganchi (DoB 28/01/1971); Mr Zubair Ismail (DoB 06/12/1984).”

Ganchi and Ismail were held in jail in Pakistan in 2004 after being arrested by anti-terrorist police hunting al-Qaida members. The two said they had been planning a trek in Pakistan and were released, returning to South Africa.

In the runup to the Seoul summit, Naidoo called for action over climate change, international poverty and gender inequality, and for global tax initiatives to back it up. He was involved in the anti-apartheid movement as a teenager and arrested several times. After a period in exile in the UK, he returned to South Africa after the release of Nelson Mandela and worked for the African National Congress.

Greenpeace and other environmental groups have long been the target of extensive intelligence operations, both by governments and corporations, across the world. In 1985, the Greenpeace flagship Rainbow Warrior was sunk by French intelligence agents in Auckland, New Zealand, on its way to protest against a French nuclear test, killing a photographer. The FBI, undercover British police and corporations such as Shell and BP have targeted or used private security firms to spy on Greenpeace.

The leaked cables show South African intelligence turning down politically motivated requests for information about opposition activists from other spy agencies – including from Cameroon on the country’s opposition leader, Pierre Mila Assouté, and from Sri Lanka about Tamil groups operating in South Africa.

Another document sheds some light on the CIA’s involvement in climate change issues.

The reasons for the CIA’s interest are not clear. It may see climate change as a potential source of conflict and want to explore possible consequences. Some see a potentially more sinister motivation.

A senior US climate scientist, Alan Robock, based at Rutgers University in New Jersey, expressed concern this month that the CIA and other intelligence agencies were funding climate change research to learn if new technologies could be used as potential weapons.

Robock, writing in the Guardian, said he had been approached by two men calling themselves consultants for the CIA who asked whether the US would be able to detect another country trying to control the US weather. Robock added: “At the same time, I wondered whether they also wanted to know if others would know about it, if the CIA was controlling the world’s climate.”

The CIA established the Center on Climate Change and National Security in 2009, a move heavily criticised by Republicans. Although the centre was closed down in 2012, the CIA said it would continue to monitor the security implications of climate change. A CIA document, part of the leaked cache, is focused on renewable energy.

The centre asked partner agencies in 2011 in the UK, Australia and South Africa to help explore the potential for renewable energy sources. The leaked document, marked confidential, is described as a joint intelligence product of the CIA, the UK, Australia and South Africa. “This effort is intended to provide the CIA with a deeper understanding of the potential for ramping up renewable and clean energy in key parts of the world and a better understanding of the collection capabilities and interests on renewables in the UK, South Africa and Australia,” the document says.

The project looks at “wind, solar, biomass and geothermal for electricity generation and alternative fuels for transportation”. A South African intelligence official, responding to the CIA request, wrote: “The issue area of ‘renewables’ have become even more strategic in the last several weeks, as the UK, Germany and now the US have established long-term energy strategies requiring 80% dependence on renewable and clean energy by the 2035-2050 period.

“At this early stage, we have already identified numerous challenges and potential problems with such ambitious targets but our joint paper will certainly be well-timed.”

Within the US federal government, the Pentagon, like the CIA, has shown enormous interest in climate change, anticipating potential conflict as a result of climate change. In the document, the CIA suggests the four intelligence agencies look jointly at the role of renewables in tackling climate change, with the UK taking the lead in alternative fuels for transport to offset oil and the geopolitics of renewable energy, while the CIA looked at issues such as “possible unintended consequences”.

The CIA climate change centre was closed in 2012 without an announcement or explanation following the replacement of Leon Panetta as CIA director by General David Petraeus in November 2011.