Just three days after my homeland was devastated by typhoon Haiyan, the biggest storm ever to hit land, I attended the opening of the UN climate change talks in Poland. With a deep sense of anxiety about the fate of my family and friends, I pleaded with delegates to recognise that vulnerable countries such as the Philippines cannot cope with the overwhelming impacts of climate change alone.

On Tuesday, governments meet in Japan to discuss a major new scientific report by the Intergovernmental Panel on Climate Change. The study outlines the scale of the threat climate change poses to people worldwide and suggests ways to help people cope.

One of the most serious risks we face is escalating hunger. No civilisation can flourish without food; many have perished following the crash of food and water systems.

Climate change is making people hungry. It will change what we all eat. Extreme weather events such as typhoon Haiyan, unpredictable seasons, increasing temperatures and rising sea levels are already causing chaos for farmers and fisherfolk. Food prices are going up. Food quality is going down. By 2050, 50 million more people – equivalent to the population of Spain – will be at risk of going hungry because of climate change.

Typhoon Haiyan devastated my country. Thousands of people perished and millions more lost their homes and livelihoods. My own family witnessed the storm at close quarters. Along with millions of other survivors, they continue to be haunted by painful memories of their ordeal.

Today, millions of my people live in damaged homes and continue to rely on emergency relief to survive. More than 1 million farming households and 20,000 fishing households are struggling to pick up the pieces; the challenge is daunting. Thirty-three million coconut trees were flattened by the storm, and more than 100,000 hectares of rice fields were ruined. The overall losses in the agriculture sector could come close to $1bn (£606m).

But the story does not end here. The prospect of a serious global food crisis looms on the horizon because of the worsening impacts of climate change. Yet, as events in the Philippines show – and a new Oxfam report, 'Hot and hungry:how to stop climate change derailing the fight against hunger,' underlines – our food systems are woefully unprepared for the challenge. No country, rich or poor, can afford to be complacent. But it is the world's poorest and most food insecure countries that are the least prepared and most at risk. They stand to suffer the most.

We are at a critical moment in history and the window of opportunity is narrow. Time is not on our side.

We need urgent support for adaptation, particularly in the poorest and most vulnerable countries, to stop millions more people from going hungry in the next two decades as a result of climate change impacts that are already locked in. This need not break the bank. Poor countries' adaptation needs are estimated to be about $100bn a year – equivalent to just 5% of the wealth of the world's richest 100 people.

We also need urgent and ambitious emissions reductions to avoid a runaway global food crisis that could have grave repercussions for our children's lives. Our addiction to dirty energy stands in the way of a global solution to the problem of climate change and food. We must end this fossil-fuel gluttony.

People all over the world are already fighting climate change. Unfortunately, too few governments and big businesses are taking the threat seriously enough. We must act together to put pressure on them – and make changes in our own lives – in order to stop climate change from worsening hunger in our world.

We are at war with climate change and hunger. It is a war we cannot afford to lose. But a war I believe we can win together.

Naderev M Saño is climate change commissioner for the Philippines