UNICEF, the UN children's agency, has warned that global warming is already affecting the prospects for children in the world's poorer countries.
According to a report by BBC News, as a result of climate change, increases in floods, droughts and insect-borne disease will all affect health, education and welfare.
While richer societies can adjust, poorer ones do not have the resources, the report said.
"Those who have contributed least to climate change - the world's poorest children - are suffering the most," said David Bull, executive director of Unicef UK.
The 2006 Stern Review concluded that climate change could increase annual child deaths in sub-Saharan Africa and South Asia by up to 160,000 through GDP loss alone.
"If the world does not act now to mitigate and adapt to the risks and realities of climate change, we will seriously hamper efforts to reach the Millennium Development Goals (MDGs) by 2015 and sustain development progress thereafter," he added.
The eight Millennium Goals include such targets as eradicating extreme poverty and hunger, reducing infant mortality rates by two-thirds and halting the spread of diseases such as HIV and malaria.
Progress has been good in some parts of the world, but earlier this month the World Bank warned some targets were likely to be missed; sub-Saharan Africa was likely to miss all eight, the Bank said.
According to Unicef, climate change is already making achieving them more difficult.
Agricultural productivity is forecast to decline markedly in most of Africa, South Asia and Latin America; countries such as Zambia are already seeing a significant reduction in rainfall; the threat of waterborne diseases such as cholera is projected to increase.
"All the essential effects we are seeing now are associated with a temperature increase since 1850 of less than 1 degree Celsius," said Sir Nicholas Stern.
"Past actions and the likely trend of emissions imply that another 1-2 degree Celsius will be hard to avoid," he added.