"Advanced and emerging market economies have contributed the lion's share to actual and projected warming," argues the IMF. "Helping low-income countries cope with its consequences is both a moral duty and sound global economic policy."
Low-income countries bear the brunt
With an unprecedented increase in global temperatures over the past 40 years, and significant further warming predicted unless greenhouse gas emissions are massively reduced, low-income countries are set to suffer the worst of the extreme droughts, floods and rising sea levels that will result – even if their emissions are relatively low.
"The Earth's warming affects countries very unequally," say the authors of the report in the IMF Blog. "Even though low-income countries have contributed very little to greenhouse gas emissions, they would bear the brunt of the adverse consequences of rising temperatures, since they tend to be situated in some of the hottest parts of the Earth."
Countries in Africa, Asia and Central and South America will feel the effects of rising temperatures more than most.
The IMF notes that a 1 degree increase in temperature in a country with an average annual temperature of 25 degrees – such as Bangladesh or Haiti – will initially reduce per capita output by up to 1.5 percent, a level that will rise to 10 percent by the end of the century if there are not adequate global efforts to curb emissions.
Economies in hot countries will be effected on various levels, including lower agricultural yields, reduced worker productivity, slow investment, and damaged health. Close to 60 percent of the world's population currently resides in countries that are vulnerable to such climate change consequences – a number that's projected to rise to 75 percent by the end of the century.
Climate change-induced conflict and migration
If higher temperatures potentially cause more natural disasters, this will also fuel greater conflict and migration, argues the IMF.
"The cross-border spillovers from these impacts of climate change in vulnerable countries could be very sizable, and advanced economies will not be immune either."
Nonetheless, the report also cites research that shows that migration is largely limited to those who can afford to travel; and that people in low-income developing countries are generally trapped amid weather disasters triggered by climate change.
"Given the constraints faced by low-income countries, the international community must play a key role in supporting these countries' efforts to cope with climate change—a global threat to which they have contributed little," say the IMF.
The report notes that low-income countries would need to increase public spending by up to 30 percent of GDP if they are to achieve attaining the Sustainable Development Goals (SDGs) designed to combat climate change. Most don't have the money.
"Low-income countries also often lack the institutional setting, administrative capacity, or political stability to implement appropriate macroeconomic policies or adaptation strategies," says the IMF.
"Going forward, only a global effort to contain carbon emissions to levels consistent with an acceptable increase in temperature can limit the long-term risks of climate change."
Africa is running out of water
In the event of a global temperature increase of two degrees Celsius (3.6 degrees Fahrenheit), the World Bank predicts that southern Africa would experience up to thirty percent less rainfall. The result: an increased risk of drought. During an extremely dry period in the mid-1990s, herdsmen in Ethiopia lost around half their animals.
Too much rain
In East Africa, there could be more rain in future - not spread equally throughout the year but pouring down on just a few consecutive days. In 2011 torrential rainfall hit the Tanzanian port city of Dar Es Salaam, flooding entire districts. 10,000 people had to be housed in emergency accommodation. At least 23 people died.
Smaller harvests, more hunger
In Africa small farmers produce some 90 percent of the continent's harvests. If crop resistance to the increasing droughts, floods and other weather disasters does not improve greatly, up to 20 percent more people will suffer hunger by 2050, the UN estimates.
Malnutrition resulting from poor harvests is already a problem in many countries. Many people move to city slums where diseases like cholera quickly spread. If temperatures rise, other diseases like malaria could also spread more quickly - for example in the East African highlands, a region that is currently malaria-free.
Higher temperatures influence entire eco-systems. Many plants and animals cannot adapt to the changing conditions quickly enough. A report by the World Climate Council says that between 20 and 30 percent of all species face extinction as a result of climate change.
No more snow on Kilimanjaro
The covering of ice on Mount Kilimanjaro is almost 12,000 years old. In the last 100 years more than 80 percent of the ice fields have disappeared. A research group in Ohio has calculated that if this continues, the ice will have vanished completely by 2033 at the latest. They say drought and reduced snowfall would be the main reasons.
When the last tree is felled.....
Much of the responsibility for climate change lies with power plants, factories and automobiles in the US, Europe and Asia. But the felling of many African forests, for example to obtain charcoal, increases the amount of CO2 in the atmosphere and contributes to the destruction of the soil.
Replanting the forests
Many people have now realised that they have to act to counter the effects of climate change. For decades, environmentally aware Kenyans have been planting new trees and the area covered by forest is expanding. The trees prevent valuable farmland from being eroded - and they absorb the greenhouse gas CO2.
Protection through variety
Monocultures are very susceptible to drought or attack by pests. If different types of fruit are grown together, then there is still a harvest if one of them fails. According to the UN Environment Program (UNEP) ecological agriculture increases resistance to the consequences of climate change more effectively than conventional farming.
Action, not just words
Underground rainwater reservoirs, insurance schemes that act as a buffer when harvests fail - there are many ways to soften the effects of climate change. Development aid and climate protection must go hand in hand, stressed delegates at a recent UN conference. However, no concrete projects were put forward.
Hopes pinned on Paris
"Climate justice now!" demonstrators called at at a UN climate conference in Durban, South Africa, four years ago. They are now looking towards the end of this year when climate change will be discussed in Paris. There, the first global climate agreement could be adopted, with the goal of restricting the effects of climate change and keeping the global warming increase to two degrees Celsius.