Cancún must be about more than climate change

Twelve months ago I stood up in front of heads of state at the UN climate talks in Copenhagen and told them that they could not negotiate with the climate; they would have to negotiate with each other. And as leaders prepare to meet again in Cancún next week, I repeat my plea.

I have been attending UN conferences since 1976 and am now part of the millennium development goals advocacy group. In the past 30 years I have seen much to be proud of, and much for us to hang our heads at. At times when action has been needed, the world has responded. Other times we have not.

Negotiating an issue that has such a vast effect on our world is not easy, and governments know that negotiations are as much about how countries interact as they are about what they agree. There is a history of accidental and deliberate misunderstanding in climate negotiations that has left deep scars, but leaders must overcome this legacy of mistrust by building on common ground in a genuine, fair and trusting way that is based on mutual responsibility – to ourselves and to billions around the world.

I believe in the ability of humanity to come together in the face of seemingly impossible difficulties. Finding a way to rise to the challenge of climate change is not easy. But it is possible. We have the knowledge to deliver – the cost of low-carbon technology is falling, our understanding of how climate change will affect our lives is improving. The UN advisory group on climate finance has shown that we can generate the $100bn (£64bn) a year promised to tackle climate change. Now we must work together to make these possibilities a reality.

It is true that no delegate leaves a conference with a perfect document, but last year in Copenhagen we caught a glimpse of the potential we have if we tackle this global crisis together. For the first time, 115 countries recognised the scientific case for restricting the rise in global temperatures to 2C. For the first time ever, all the major emitters of the world accepted their moral responsibility to reduce their emissions and committed to build trust and transparency. And for the first time ever, we set out our interconnectedness, with developed countries offering to help the poorest countries to protect their people from climate change and to find a path to low-carbon sustainable development.

We appreciate the fact that an international agreement alone will not deliver the answer – words and promises mean nothing without action. Trust is a two-way road and outside of Cancún, governments must do what they have promised: take concrete action to reduce their emissions; deliver finance and work together to make low-carbon development a reality; and protect those least able to cope with the impact of climate change.

If we are to help steer the world through this uncertainty, we must be clear that climate change, though important, is only one part of the puzzle. If we truly want to tackle climate change, poverty and conflict we need to think holistically. We need to, as Ban Ki-moon said at the launch of the UN global sustainability panel, "think big, connecting the dots between poverty, energy, food, water, environmental pressure and climate change".

Focusing on only one dot means that we lose sight of the bigger picture. Water is a timeless example. We know that the impact of climate change will be felt through water – too much, too little or the wrong type. And improving basic services such as water sanitation and hygiene is vital to development, reducing child deaths and improving education. There are 884 million people who don't have safe drinking water and 2.6 billion who don't have somewhere to go to the toilet. The floods in Pakistan are a dramatic example of how destructive water can be, yet how essential it is to life. Reducing disaster risk, and providing the most vulnerable with safe water and sanitation is as much about building their resilience to climate change as it is about justice, equality and development.

And we saw in 2008 just what can happen when we fail to connect those dots – climate change, oil prices, protectionism and global economics collided to push food prices up and hang a cloud of starvation over the heads of millions of people.

So these negotiations are about more than climate change – we need to find reason to trust each other so that we can find a new way of working together to tackle the connected global challenges we face. Our failure to link these issues affects us all. In Cancún and beyond, the governments of the world have to learn to work together for our common future. Our planet is finite, our fates are intertwined, our choice is clear – stand together or fall divided.

Wangari Maathai, the 2004 Nobel Peace Laureate and founder of the Green Belt Movement