International Judo Federation (IJF) President Marius Vizer wants people to mark World Judo Day by planting a tree.
World Judo Day is held every year on October 28 to celebrate the birthday of Kano Jigoro, the founder of the sport.
National Federations and judo clubs around the world are encouraged to take part in the celebration.
This year Vizer wants to use it as an opportunity to raise the awareness of climate change.
"On the occasion of World Judo Day 2019, I would like to congratulate the entire world judo community for all their activities and to wish all of you continued success and good results in your work," he said in a message.
"I would like to thank all those who joined the IJF initiative to 'Plant a Tree' on this special day,
"I believe we can all be proud of showing an example of unity in the global fight against climate change.
"Climate change is an issue that concerns all of us and that will especially affect our children.
"We can all do something to have a positive impact on our environment.
"More than 25 countries already joined the movement, and more than 1,300 trees have been planted so far.
"You are all welcome to join us on this special day to propose a better place to live in to the youth of the world."