Vanessa Nakate, a Goodwill Ambassador for the United Nations' children's fund UNICEF, urged U.S. President Joe Biden to listen to climate science and those "on the frontlines of this crisis."
"The world needs the United States to be a climate leader in our fight for climate justice," the 25-year-old told AFP in an interview at the COP27 climate conference underway in Egypt's Sharm el-Sheikh.
"The message is for President Biden to stand with the people on the planet and the coming generations."
Although she is unlikely to meet the US president in person during his fleeting trip to the two-week climate talks, Nakate urged Biden to summon the "political will" to support communities most affected by the snowballing impacts caused by a warming world.
Nakate said she had been compelled to attend COP27 because of the growing harm suffered by people in the global south, adding that activists were using social media and interviews in the press to keep up the pressure on leaders.
She said it was more important than ever "to hold our leaders accountable and to remind them that we cannot eat coal, we cannot drink oil and we cannot breathe gas."
She called for the international community to step up investments that address energy poverty in Africa and support the shift to renewable power.
"If there is no climate finance to support that transition, many of our countries are being pressured into taking money from fossil fuel companies so that they can lift their communities out of energy poverty," she said.
"In a world gripped by energy, food and inflation crises - fueled by climate impacts, the war in Ukraine, and the pandemic -- the challenges of soaring prices are too often seen only through the eyes of wealthier nations," Nakate said.
"In countries like Uganda, many people are being impacted and suffering because, as the fuel prices rise, transportation rises, food prices rise as well," she added, saying many people "just don't know how to keep up with it."
Nakate noted that Biden and the other world leaders who have travelled to Egypt this week should understand that their positive actions also have the potential to echo into the future.
"I've heard of something called the butterfly effect, whereby just one thing that may seem like a small action can end up affecting the lives of so many people," she said, adding that leaders have a choice whether their effect is positive or negative.
"If it's to be positive, then one action right now will benefit not only our generation, but also the coming generations," she said.