GENEVA (Reuters) - Close to 2,000 United Nations employees have called for the global body to reduce its carbon footprint, including through curbs on their own diplomatic perks like business-class flights and travel handouts, a letter obtained by Reuters showed.

The United Nations calls climate change the "defining issue of our time" and is hosting a New York summit on it next week. But reformers within say in the letter addressed to Secretary-General Antonio Guterres that it needs more radical change to get its own house in order.