Mankind has a problem. We're heating the Earth and destroying its ecosystems so fast that we're killing off life as we know it. The fragile world around us, from rainforest canopies to marine life in our oceans, is the life support system we all depend on – for food, for shelter, for clean air. But we're trashing it, quickly, many habitats at a time, and putting ourselves in grave danger within our lifetimes.

The overriding challenge of our generation is to protect the world around us – there is no planet B. We must halt biodiversity loss before it is too late and precious species go for good. Reducing our ecological footprint goes hand in hand with tackling climate change. It means putting the breaks on our damaging consumption habits and living fairly within our environmental limits – making wiser use of resources and clean energy.

The Guardian's Biodiversity 100 campaign is one way of saying enough's enough. Taking collective action to ask governments to protect ecosystems is the best way of getting our voices heard. National targets for protecting biodiversity have been missed year after year, but the meeting of the Convention on Biological Diversity in Japan this October is a chance to put that right – and it's up to all of us to hold world leaders to account.

Yes it's an international problem and yes every nation can help solve it, but it's only fair that rich countries take the lead. We can't criticise others until our own house is in order – and the UK has a lot to put right. Friends of the Earth's 2008 report What's feeding our food? revealed an unsavoury truth: rainforests and wildlife in South America are being destroyed to make way for vast soy plantations to grow animal feed for Britain's factory farms. The very sausage on your barbecue or burger in your bun is costing forest habitats – it's enough to leave a bitter taste in your mouth.

Many unique ecosystems like the Atlantic Forest and Cerrado grasslands in South America are being decimated by soy farming and cattle ranching. The Atlantic Forest, which runs along the eastern coast of Brazil and inland to Paraguay, Argentina and Uruguay, is one of the world's biodiversity hotspots. It is home to around 8,000 unique plant species and more than 20 critically endangered species including the white-collared kite, and black-faced lion tamarin. 92 per cent of its amphibians are unique to the area. It's shocking that agricultural activity here has shrunk the forest to less than a tenth of its original size, as trees have been cleared to make way for ranches and soy plantations, and small farmers pushed deeper into the forests. Worrying too, that in 2010, the region of Brazil containing the remaining Atlantic Forest showed the biggest increase in soy plantations in the whole country.

Rainforest and wildlife in South East Asia are also being lost – this time in the EU's drive for biofuels. But biofuels are far from the green energy solution big business says they are. The habitats of the orangutan and Sumatran tiger are being trashed in Malaysia and Indonesia to make way for biofuel crop, and in 2008 the UN estimated that if logging rates continue, virtually all rainforest there will be destroyed by 2013. Worse still, Friends of the Earth research in 2009 revealed that biofuels could even be contributing more carbon emissions than the fossil fuels they replace, equivalent to putting half a million extra cars on the roads.

To stop this habitat destruction – and the additional atmospheric carbon that is exacerbating climate change – there needs to be some urgent rethinking. The good news is we know the solutions – but now we must use them. Instead of spending taxpayers' money propping up factory farms, the UK government should be backing planet-friendly farming. Friends of the Earth's recent Pastures New report shows that half of the animal feed imported to the UK could be replaced with home-grown alternatives – saving an area of forest the size of the Yorkshire Dales every year. More than 40,000 people have backed our campaign so far – and we've got a Sustainable Livestock Bill in parliament as a result. If successful it will overhaul UK farming, benefiting both farmers in Britain and biodiversity here and abroad – so we're urging MPs to back it.

Similarly the EU's target to fuel 10% of road transport with biofuels by 2020 is impossible to reach sustainably – the expansion of plantations for biofuel crops such as palm oil is the main driver of deforestation in south-east Asia. The UK should drop its share and promote greener alternatives to driving instead. More than half of UK car journeys are less than five miles long and many of these could be completed by other means. The government should fund local schemes that get people walking, cycling and using the bus, and make rail a cheaper and more convenient option for longer trips.

2010 is the UN year of biodiversity, but the world's species and habitats are millennia old. If we fail to take bold action to protect the colourful diversity of life on Earth, for the sake of the world's people and future generations, the world will not only be greyer, but life-threatening for us and future generations.