In support of the event, Johannesburg City Parks, in conjunction with United Nations Development Programme donated 12 Rhuslancea trees to the school to add to the trees it already has. “The significance of World Environment Day is to remind the world how human activities affect and damage the environment,” said the environment and education specialist, Nicole Ferguson.

“To encourage people to take responsibility for this damage and take action to reduce and redress some of the damage that has already been done. If anyone was to save the world [they] must plant a tree.”

Ferguson led teachings about the role played by trees in minimising global warming. “Trees and plants capture carbon dioxide during photosynthesis by removing the most abundant greenhouse gas from the atmosphere and storing some of it in their woody tissues.”

Photosynthesis is a chemical process that converts carbon dioxide into organic compounds using the energy from sunlight.

Children also shared their knowledge about the importance of planting trees. “Trees are important because they clean poisonous gases from filling the sky,” said 11-year-old Thapelo Mokhetle, who is in Grade 6. Mokhetle’s peers did not want to be outdone: “Trees provide us with shelter, oxygen, food and fresh air,” said another youngster.

The school’s natural science teacher, Ndabezinhle Ndlovu, said that in the classroom, he emphasised preservation of the environment and global warming. “We teach these lessons in class. I am happy today that Johannesburg City Parks has granted a platform to expose our learners to the practical side of natural sciences.”

Ferguson said City Parks was committed to dealing with environmental challenges. “We are faced with many challenges, especially in a densely populated area like Alexandra, such as illegal dumping, leaking sewers, erosion, pollution, litter and smoke.

“These threaten the environment and our health, but effects of these can be limited by planting trees; for example, less soil is washed away in summer rain and [there is] less dust in winter.”

City Parks has planted over 200 000 trees in Johannesburg in recent years, an achievement that has contributed immensely to making Johannesburg an urban forest, according to Ferguson.

School principal, Thembakazi Giyama, said the event would help the learners a great deal in understanding the importance of preserving the surroundings.

“Our school is located right in the middle of informal settlements, where illegal dumping is rife. I am sure that from today our children have learned something.”

She pointed out that the preserving the environment was not a one-day event, but must be practised every day.

In concluding the activities of the day, a representative from the United Nation Development Programme, Almaz Gebru, read out a special message from the secretary-general, Ban Ki-Moon.

“Despite growing global awareness of the dangers of environmental decline, including climate change, biodiversity loss and desertification, progress since Earth Summit has been slow.

“We will not build a just and equitable world unless we give equal weight to all three pillars of sustainable development, social, economic and environmental,” read part of the message.

The first Earth Summit was held in 1992. In exactly one year’s time, world leaders will converge once again in Rio de Janeiro, Brazil, for the UN Conference on Sustainable Environment.

In 2009, solutions to deal with global warming were discussed at the Copenhagen Climate Conference.