It's easy to be happy when you're younger. You're not as bothered by issues such as this. I'm pretty happy now, although I can feel the effects of climate change around me. I trained as an ecologist and for years worked on scarlet macaw conservation in Costa Rica. Climate change was becoming an issue for parrots, with the wet winters affecting breeding habits.

I lived relatively simply in Costa Rica and I'm trying to be green in the UK, but I do consume more. There's a lot of focus put on changing our lifestyles. A change of behaviour can make people happy, but they must be given incentives. Bus and train fares? Still horrendous.

I'm getting better at accepting the bad news and not letting it make me unhappy. You'll hear about some company getting their wicked way despite going against the general consensus of the people, but any hopelessness is balanced by knowing I'm doing what I can. At one lecture I was told the Amazon could feasibly dry out. You hear that and feel terrible, but it's not going to help if everyone's hopelessly depressed.

Happiness doesn't seem to be related to the GDP or to consuming more. People living simpler lives get on with it. It's less complicated. I'm happy being surrounded by people I trust and love: my sisters, my family. To have fun but not feel as if you're letting go of your principles - that's happiness.