Africa's children are exceptionally vulnerable to climate change and are "sadly" ignored by those responsible for funding the fight against global warming, UNICEF has warned.   Africa, a continent of 1.2 billion people, is home to some of the countries least responsible for carbon emissions, but they are disproportionately affected by droughts, floods, storms and heat waves.   Children in 48 of the 49 countries assessed are at "high or extremely high" risk of being affected by climate change, according to Unicef, the UN children's agency, in a report titled "Time to Act."   "The youngest members of African society are the most affected by the harsh effects of climate change," said Lieke van de Wiel, UNICEF deputy director for Eastern and Southern Africa.   "They are the least able to cope due to their physiological vulnerability, and their poor access to essential social services. Additionally, they are underserved by key climate finance flows needed to help them adapt, survive and respond to the crisis." climate," he added, according to a cable from the AFP agency.