The United Nations warned that a "silent tsunami" caused by expensive food is putting 100 million people at risk. Aid groups argued that restricting exports would worsen 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 driving up food prices. The World Food Programme (WFP) described the crisis as a "silent tsunami" threatening to push over 100 million people into hunger worldwide. Riots in poor countries have erupted due to sharp increases in food prices attributed to various factors such as high fuel costs, adverse weather conditions, increased demand, and the use of land for biofuel production. Rice prices from Thailand, the leading exporter globally, have increased by over 100% this year. Several major food exporting countries such as Indonesia, Kazakhstan, Egypt, and Cambodia have restricted food exports in order to ensure their own supplies. The problem has been worsened by artificially induced shortages, with the world consuming more than it produces for the past three years. As a result, the World Food Programme (WFP) is facing financial constraints and has had to reduce school feeding programs in certain countries. The WFP, which initially estimated needing $2.9 billion in 2008 for its operations, now anticipates having to increase that amount by 25% due to the sharp rise in staple food prices. The end of an era was marked by Britain pledging $900 million to assist the WFP in addressing immediate issues, while Brown expressed concerns about using crops for fuel production. He mentioned the possibility of revising the UK's approach and advocating for changes in EU biofuels targets. Japanese Agriculture Minister Masatoshi Wakabayashi suggested that the WTO establish clear guidelines for food export restrictions imposed by producer nations. The Asian Development Bank's managing director general, Rajat Nag, stated that the era of inexpensive food was coming to an end and advised Asian governments against distorting markets with export limitations, but instead using fiscal measures to assist the less fortunate. U.N. Secretary-General Ban Ki-moon has warned that rising food prices could undo efforts to reduce poverty. Former Secretary-General Kofi Annan also highlighted the impact of climate change on global food security, stating that many poor countries are at risk of experiencing severe hunger crises. He emphasized that the most vulnerable populations are suffering the most from climate change, despite having the least responsibility for it. Annan called for those responsible for environmental damage to bear the consequences, stressing that climate change poses a comprehensive threat to various aspects of society, including health, security, and political stability.