GLASGOW, Scotland — Climate activist Greta Thunberg said Friday that the COP26 climate summit is a failure, lambasting the U.N.-brokered talks for turning into a public relations exercise.”It is not a secret that COP26 is a failure. It should be obvious that we cannot solve the crisis with the same methods that got us into it in the first place,” Thunberg said.”The COP has turned into a PR event, where leaders are giving beautiful speeches and announcing fancy commitments and targets, while behind the curtains governments of the Global North countries are still refusing to take any drastic climate action.”She was speaking on stage shortly after a strike organized by “Fridays For Future” saw thousands march 1.6 miles from Kelvingrove Park to George Park in Glasgow’s city center — less than 2 miles from where the COP26 event is being held.The U.K. is presiding over COP26 through to Nov. 12, a major climate event regarded as one of the most important diplomatic meetings in history.It has yielded some positive developments, including pledges to end and reverse deforestation, a deal to cut methane emission levels by 30% by 2030 and new commitments to phase out coal power.However, experts harbor deep concerns about whether countries and companies can keep the 1.5 degrees Celsius goal alive. This critically important temperature threshold refers to the aspirational target of the landmark 2015 Paris Agreement.Thunberg said COP26 had been described as “the most exclusionary COP ever,” saying those at the sharp end of the climate crisis remain unheard. She added that the event could be considered a “two-week-long celebration of business as usual and blah, blah, blah.”A COP26 spokesperson said in a statement given to CNBC: “The UK is committed to hosting an inclusive COP.””Ensuring that the voices of those most affected by climate change are heard is a priority for the COP26 Presidency, and if we are to deliver for our planet, we need all countries and civil society to bring their ideas and ambition to Glasgow,” they added.Policymakers and business leaders are under immense pressure to meet the demands of the climate emergency at COP26. Yet, even as many publicly acknowledge the necessity of transitioning to a low-carbon society, hopes of limiting global heating to 1.5 degrees Celsius are quickly deteriorating.Climate scientists have repeatedly stressed that the best weapon to tackle rising global temperatures is to cut greenhouse gas emissions — fast.Thunberg was catapulted to fame for skipping school every Friday to hold a weekly vigil outside the Swedish Parliament in 2018. It sparked an international wave of school strikes, with millions of children taking part in rallies around the world.”Once again we are faced with another COP event. How many more of these should they hold until they realize that their inactions are destroying the planet?” Vanessa Nakate, a climate activist from Uganda, said at the same event on Friday.”Today we shall continue to fight on, everywhere we can. We cannot give up now. We need to continue holding leaders accountable for their actions. We cannot keep quiet about climate injustice,” she added.’Change is not going to come from inside there’Speaking at a protest outside of the COP26 complex earlier this week, Thunberg once again slammed world leaders for not doing enough to meet the demands of the climate emergency.”This COP26 is so far just like the previous COPs — and that has led us nowhere,” Thunberg said on Monday as she addressed climate activists.”Inside COP, there are just politicians and people in power pretending to take our future seriously,” she said. “Change is not going to come from inside there, that is not leadership. This is leadership, this is what leadership looks like.”She had previously voiced her frustration over climate inaction at the Youth4Climate summit in Milan, Italy in late September.”Net zero by 2050. Blah, blah, blah. Net zero. Blah, blah, blah. Climate neutral. Blah, blah, blah. This is all we hear from our so-called leaders. Words that sound great but so far have led to no action. Our hopes and dreams drown in their empty words and promises,” Thunberg said at the time.Read more about clean energy from CNBC Pro