Recently, the world was shocked to see images of a protest in India where farmers burned photographs of climate leader Greta Thunberg, who at a very young age, became one of the most critical and courageous voices in the fight for the climate. 

Thunberg, whose child-like image in her yellow raincoat is already iconic, is an 18-year-old teenager. But her heirs are very young and fight for similar causes in their respective countries, where they often endanger their lives. 

This is the case of Francisco Vera, who is nicknamed "the environmentalist child" in Colombia, but whose courage, maturity and ardent defense of the climate make him much more than that. 

Francisco began his activism at the age of six, when he attended protests against bullfighting with his family. 

His early vocation and love for nature led him to become involved in many other campaigns in favor of nature reserves and against mining, or in recycling actions, until he founded an environmental group called Guardians of Life at the age nine. 

At first, he told the BBC, it was just him and six friends, but now there are more than 200 people following Vera all over Colombia and even outside the country. 

Being a "guardian of life" carries many risks, especially in Colombia, which tops the world's list of environmentalists killed by hitmen working for mining or large-scale farming interests. 

Vera had already tirelessly denounced these issues and had been taunted on the Internet, his mother said, but when the COVID-19 pandemic hit and the country came to a standstill, the young activist, also famous for his defense of children's rights, demanded an urgent improvement in access to education. 

And then Francisco began to receive death threats. The first on last Jan. 15, when he received an anonymous Twitter message after publishing a video in which he asked the government to improve Internet connection for children studying at home. 

The incident shocked Colombia and those who monitor and account for the frequent aggressions received by community leaders. 

"These types of threats are common and often go unpunished," activist Lourdes Castro of Somos Defensores told the BBC. 

"Threatening an 11-year-old boy only shows that we have reached new levels of intolerance and lack of respect for freedom of expression," she denounced. 

Following the incident, the UN High Commissioner for Human Rights, Michelle Bachelet, sent a letter to Vera thanking him for his activism and his "passion for protecting the planet," and agreeing with him about the need for a better Internet connection for all children around the world. 

The environmentalist celebrated the recognition, but also had some words for those who try to undermine freedom of expression with violence.

"Criticism is part of life, and I welcome it as long as it is constructive and respectful," he said. "But obviously there is no place for insults and threats." 

Once again, children are are giving the adults lessons we should take good note of.