AMSTERDAM — Chronic hunger may be ‘the defining human tragedy of this century,’ as climate change causes growing seasons to shift, crops to fail, and storms and droughts to ravage fields, an advocacy group said. Oxfam International released a report Monday as leaders of the Group of Eight wealthiest nations prepare to meet in Italy this week, with an agenda to include both food security and climate change. It says that as the weather changes, millions of people in areas suffering food scarcity will have to give up traditional crops, possibly leading to social upheavals such as mass migrations and conflict over water resources. Rich countries in temperate climate zones, such as northern Europe and parts of the United States, will benefit from warmer weather and more rainfall, but far more people in hotter, poorer countries will face more erratic and expensive food supplies, said the British-based nonprofit group. The report, ‘Suffering the Science: Climate Change, People and Poverty,’ was meant to add urgency to the G-8 meeting and to a broader group of 17 countries, the Major Economies Forum, which convenes later in the week to try to unblock negotiations on a new climate change […]