The United Nations warned of a "silent tsunami" caused by expensive food that could impact 100 million people. Aid groups expressed concern that limiting exports would exacerbate the situation. Prime Minister Gordon Brown stated that Britain would push for changes to EU biofuels targets if it was proven that growing crops for fuel was contributing to high food prices. The World Food Programme described the situation as a new form of hunger affecting millions of people who were not previously at risk. Riots in poor Asian and African nations have erupted due to soaring food prices influenced by various factors such as costly fuel, adverse weather conditions, increased demand from rising incomes, and the conversion of land for biofuel production. The price of rice from Thailand, the leading exporter globally, has increased by more than 100% this year. Several major food exporting countries, such as Indonesia, Kazakhstan, Egypt, and Cambodia, have implemented restrictions on food exports in order to ensure their own supplies. According to Sheeran, shortages that have been artificially created have worsened the situation, as the world has been consuming more than it has been producing for the past three years, leading to a depletion of stocks. The rising prices have caused the World Food Programme to face financial challenges in purchasing food for its programs, resulting in cutbacks to school feeding initiatives in Tajikistan, Kenya, and Cambodia. The WFP, which had initially estimated it would need $2.9 billion in 2008 to meet its needs, now anticipates having to increase that amount by 25% due to the sharp increase in prices of essential grains like wheat, maize, and rice. The end of an era was marked by Britain's pledge of $900 million to assist the WFP in addressing immediate issues, as well as Brown expressing concerns about using crops for fuel production. He mentioned the possibility of changing their approach based on a UK review, and indicated a push for change in EU biofuels targets. Japanese Agriculture Minister Masatoshi Wakabayashi proposed clear rules for food export restrictions at the World Trade Organisation, allowing importers like Japan to provide input on restrictions imposed by exporting countries. Asian Development Bank's managing director general, Rajat Nag, stated that the era of cheap food was over and advised against market distortion through export curbs, advocating for fiscal measures to aid the poor. U.N. Secretary-General Ban Ki-moon has warned that rising food prices could undo efforts to reduce poverty. Kofi Annan, the former Secretary-General, has stated that climate change is worsening the global food crisis and could lead to severe hunger crises in many developing countries. He emphasized that the poor, who are least responsible for climate change, are suffering the most and called for those responsible for pollution to take responsibility. Annan also highlighted the broad impact of climate change on health, security, political stability, and social cohesion.