Rising global health risks driven by climate change will hit the poorest, most vulnerable people the hardest - and failure to prepare for those threats will mean more deaths and suffering, a leading environmental health scientist told Thomson Reuters Foundation. From impoverished families living in flood-prone homes to women whose cultures require them to stay covered in extreme heat, climate impacts on health have "a strong equity component", said Kristie Ebi, a professor at the University of Washingtons Center for Health and the Global Environment. Besides hiking dangers from deadly heat and spreading diseases, climate change will fuel a rise in basic health problems - from diarrhoea to poor nutrition - that will affect the poor most and likely widen global inequalities, she said. "Future health risks will be determined not just by the hazards created by a changing climate but also by the sensitivity of individuals and communities exposed to these hazards," she noted in an article published this month in the journal Health Affairs. Many of the biggest health concerns from climate change "boil down to maternal and child health issues", said Ebi, who has helped countries plan how to adapt to climate-linked health threats from Africa and Asia to the Pacific and Central America. Children face particular risks, she said. Because they breathe in more air for their body size than adults, for instance, they are particularly susceptible to air pollution, such as from worsening global wildfires, she noted. "They handle it much more poorly than adults do," Ebi told the Thomson Reuters Foundation in an interview. High levels of child stunting and wasting, as extreme weather destroys crops and hits food security for many families, also will drive lasting health problems, she said. "Without sufficient food, brain development is affected. Children end up learning less and earning less," said Ebi, who has led many national and international climate assessments. Health issues can feed on each other too, she said, with hunger increasing vulnerability to malaria and more frequent diarrhea exacerbating malnourishment. Preparing health services for the coming threats will be crucial to avoid the worst impacts - but both richer and poorer countries are spending too little on that, she added. Globally, less than 0.5% of international climate finance goes to efforts to address climate-related health concerns, the journal article noted. The US National Institutes of Health, for instance, spends under 1% of its research budget on climate issues, Ebi said. "Its laughably small," she said of global funding to research and deal with climate-related health concerns. Such limited funding means measures that could help stem worsening health risks - from better early warning systems to mental health support for those who suffer catastrophic losses - are not being put in place fast enough. Progress on tackling shifting health threats is also hampered because experts on related issues - from water and agriculture to nutrition and diseases - do not work together often enough, Ebi said. "We need people from different fields sitting together and solving problems," she added. "The challenges the world is facing are interconnected."