Thousands of demonstrators marched through Glasgow, the city hosting the United Nations Climate Change Conference, on Saturday, demanding greater global action.

Students, activists, and concerned citizens dressed up against the cold, joining arms as they marched west from Kelvingrove Park to the city’s center George Square.

An lively gathering of youths – some with bullhorns – blamed companies for the climate problem and yelled calls for socialism while slamming their fists in the air, carrying red flags and placards saying “Capitalism is Killing the Planet.”

Hundreds of Scottish national flags were flapping in the wind elsewhere in the crowd. Others raised the issue of climate justice and disadvantaged farmers.

A few blocks away, at the COP26 summit, which has been going on since Monday and will continue for another week, speakers spoke about how global warming is destroying farmlands and jeopardizing food security.

So far, a week of official speeches and pledges has included promises to phase out coal, limit methane emissions, and reduce deforestation. However, activists have complained that the summit has so far produced insufficient proof of progress.

On one stage at the conference, actor Idris Elba acknowledged that he had few credentials to speak on climate change, but said he was at COP26 to amplify the climate threat to global food security.

Sitting on the same panel, climate justice campaigner Vanessa Nakate of Uganda implored the world to stop burning fossil fuels, the main cause of rising global temperatures.

“We are watching farms collapse and livelihoods lost due to floods, droughts and swarms of locusts,” she said – all of which scientists say are being exacerbated by climate change.

“The climate crisis means hunger and death for many people in my country and across Africa.”

Asked about her influence in the climate talks, Nakate noted the protest outdoors.

“Change is what is happening outside, what young people are doing, organizing … climate strikes. That is where the change is,” she said.

Civil society leaders and representatives from companies like Unilever and PepsiCo spoke at the conference about corporate responsibility in making trade and commerce less of a burden on nature.

Speaking about using satellite technology to monitor global landscapes, the director and founder of Google Earth Outreach urged better stewardship of the world’s forests.

“We don’t want to be writing the obituary of our planet in high resolution,” Rebecca Moore said.