Zero point eight of a degree of warming may not seem like that much. This is how much average temperatures have risen over the past two centuries as a result of carbon pollution.
Yet this seemingly small change is already upsetting the delicate balance of the Earth's ecosystems and throwing once predictable seasons out of whack.
Closer to the poles, the warming is happening much faster than the world average. Thanks to global warming, locally grown broccoli, carrots, cauliflower, cabbage and even a few strawberries now stock supermarket shelves in ice-covered Greenland.
It might seem like a good thing for the 57,000 people who live in Greenland. But it's an example of the changing weather patterns that threaten to wreack havoc on human civilisation.
Without emergency action to cut emissions and develop sustainable farming, climate change will make some of the world's richest agricultural areas unproductive.
Climate change equals more hunger. A failure of the world's richest polluting nations to act will add millions more to the shockingly high numbers — a billion people — who are malnourished today.
The currently existing dysfunctional, profits-based food system will be unable to cope with the changes. A new report released by Oxfam on July 6 warned that climate change threatens to make famine, disease and disasters "the new normal".
"Hunger will be one of the major impacts of climate change", the report said. "It may be the defining human tragedy of this century.
"Millions of people in countries that already have food security problems will have to give up traditional crops and agricultural methods as they experience changes in the seasons that they and their ancestors have depended upon."
In February, the United Nations Environment Program (UNEP) predicted changing weather patterns, water scarcity, the spread of damaging insects and pests to new areas and land degradation would increase in many parts of the world due to climate change.
It said up to 25% of world food production might be lost by 2050 if no action are taken.
In parts of the wealthy, industrialised world (excluding Australia) crop yields may actually rise. In the US, for example, agricultural profits may rise in the short-term by as much as 4% a year due to warmer weather.
Wheat production in other major polluting nations in northern Europe and Canada may also rise — at least in the short-term.
Meanwhile, the outlook for billions of people in the global South — the people who have contributed least to the climate disaster — is dire. Climate change will change seasons, lower yields and spread hunger among the world's poorest.
Maize is a staple crop in sub-Saharan Africa. Oxfam predicts US$2 billion worth of the crop will be lost every year.
Dr Balgis Osman-Elasha, from the Higher Council for Environment and Natural Resources in Sudan, told the Copenhagen Science Conference in March that "53% of African disasters are climate-related and one-third of African people live in drought-prone areas. By 2020 yields from water-fed agriculture in Africa could be down by 50%."
Wheat production in south Asia's fertile Indo-Gangetic plain could fall by 50% by mid-century. Rice yields in the Philippines could fall by 50%-70% in a decade.
South African government officials warn of a 50% drop in the region's cereal production by 2080.
The UNEP said the disappearance of glaciers in the Himalayas due to climate change would mean no water for irrigation for about half of Asia's total cereal production by 2050. The region accounts for a quarter of world food production today and provides for almost 2 billion people.
It was more a publicity stunt than a serious commitment, but the world's richest governments, including Australia, settled for a target of 2ºC warming at the recent G8 summit. This amounts to more than a doubling of warming from now.
However, scientists say current pollution levels and government inaction will mean the planet will overshoot the 2°C target by a dangerously wide margin.
The Oxfam report pointed out that even 2°C is still far too high to prevent "death, suffering, and devastation for millions".
The rich countries have an immense ecological debt to repay the global South after centuries of pollution. Ending unfair agricultural subsidies for First World producers and massive aid and investment to develop sustainable farming must be part of this repayment.
Otherwise, up to 200 million people will become refugees every year due to hunger and land loss by 2050, Oxfam warned.
The widespread development of sustainable organic agriculture offers a way out of the looming crisis. The UNEP said a recent African study of 114 farms across 24 countries showed a marked increase in yields, while improving soil quality. Most farms doubled food production.
In some East African farms, the yield shot up by 128%.
Greenhouse emissions from unsustainable agricultural practices — mostly from big agri-business concerns — are also a big part of the climate change problem. If emissions from livestock, the use and production of synthetic fertilisers and the transport of food for long distances are included, capitalist agriculture is responsible for up to 30% of the total carbon pollution worldwide.
The dominance of corporate interests in agriculture is the biggest barrier to much needed sustainable changes in food production. Ten corporations control 67% of the world seed market. Ten large firms also control 63% of animal pharmaceuticals and 89% of the agro-chemical supply.
A shift to organic farming might save many lives, but it would hurt their profits.
Real food security for the world is possible. But it will require a decisive break from today's market-based food system — a system that drives hunger and climate change at the same time.