The five places that made me: Tim Jarvis, environmental scientist and adventurer

MALAYSIA

I grew up in Malaysia where getting lost in the jungle and monkeys were part of everyday life. As a 12-year-old, my parents would let me roam freely, I got used to my own company and the excitement of discovering things for myself – something that has never left me. To do that under my own steam was a great learning experience.

GUATEMALA

In my 20s, I worked for an aid program in Guatemala in the spectacular Cuchumatanes mountains for a year, building gravity-fed water systems for Mayan communities. I was amazed by the kindness and generosity of the people despite them having few possessions and suffering ongoing persecution. Their resilience in the face of incredible adversity always stuck with me.

NORWAY

In the 1990s I went to the Arctic to cross the island of Spitsbergen on foot. It was 500 kilometres of gruelling travel with a heavy sled, the bitter cold and the ever-present threat of polar bears. I did it pre-GPS with paper maps, a compass and a 308 rifle. The clear air, vast scale and the weight of my sled meant that I travelled incredibly slowly, which taught me humility and a patience I never knew I had.

ANTARCTICA

Having been north, it was only logical that I should head south, and in 1999 I bid to be the first person to cross Antarctica on foot and unsupported. I reached the South Pole in 47 days pulling a 225-kilogram sled and scaring a scientist at the base working outside – he hadn't expected anyone to be out there.

SOUTH GEORGIA

In 2013, I led the first retracing of polar explorer Sir Ernest Shackleton's incredible journey of survival – sailing to the subantarctic island of South Georgia and climbing over its mountainous interior. I noticed South Georgia's glaciers were melting fast due to climate change. South Georgia became the genesis behind my 25zero project, which uses melting tropical glaciers as an indicator for climate change. I now climb these mountains to highlight the urgent need for global action to prevent climate change.

As part of his 25zero project and in partnership with Kathmandu, Tim Jarvis' next major expedition will be to climb Mount Kilimanjaro in June. See 25zero.com