I see no significant move on the part of the emitters to change. So I now feel it's time for disruption.
Former Irish president Mary Robinson has warned Extinction Rebellion protesters that they risk alienating the public if they do not employ smart tactics.
The UN Special Envoy on El Nino and Climate said disruption was necessary to affect change, but that it could take many forms.
She also praised the work of Greta Thunberg, saying her address at the UN's Climate Action Summit last month brought her to tears.
Dr Robinson said: "I think what Greta and her generation are doing is humanising the issue of climate change in a very vivid way. Because what they're saying - which is correct - is that we, the adults in the world, are not guaranteeing them a safe future; a liveable future.
"I was in the UN General Assembly during the Climate Action Summit, and when I heard her say 'you have stolen my childhood' - a 16-year-old - I cried, actually. I thought, 'this is not fair'."
Speaking to the PA news agency at the Aurora Forum in Yerevan, Armenia, Dr Robinson said climate change protests were one way of causing disruption, but that the most effective method was through investors, asset managers, and pension funds.
She added: "I see no significant move on the part of the emitters to change. So I now feel it's time for disruption - and disruption takes many forms.
"Disruption can be litigation, disruption can be shareholder questions at meetings, disruption of a very effective thought can be when investors are warning about being invested in stranded assets.
"And disruption can be bottom up - the schoolchildren, the young people, the Extinction Rebellion, the women leaders. But the most effective is the investors. If they can really move that needle, it can move very fast."
Asked about Extinction Rebellion protests in London last week which saw public transport targeted, Mrs Robinson said the activists need to keep people on side.
She explained: "I hope they will be very smart about their tactics, because if they alienate the public that will put us a step backwards. So far, on the whole, they have been quite clever they've been funny.
"They've been apologetic for the disruption caused because they don't want to alienate the public. But then there are some who want to go further.
"I think it is very, very important that the public display of disruption is seen by the public as being in their interests, and that has happened. But if they lose that, that would be very serious."
Dr Robinson became the first woman president of the Republic of Ireland in 1990. She is also a former United Nations High Commissioner for Human Rights. In 2014, she was appointed to oversee UN efforts to tackle climate change.
Last November, she was appointed chairwoman of peace and human rights campaigning group The Elders.
Nina Massey is a reporter with PA. Yerevan, Armenia.