But the war has caused supply issues and driven up the price of natural gas, which is key to fertiliser production.Also speaking to the BBC, its managing director Kristalina Georgieva said the world should "move attention today to fertilisers, because this is where we see particular threat for food production and therefore food prices in 2023".'Severe impacts'Last week economists reported that sharp increases in fertiliser costs could lower food production yields so much that by the end of the decade, an increase in agricultural land equivalent to "the size of much of Western Europe" would be required to meet demand globally.While almost everyone will feel the effects of that on their weekly shop, it's the poorest people in society, who may already struggle to afford enough healthy food, who will be hit hardest."Russia is the world's largest exporter of fertiliser, so it will have global implications."