Coverage of the recent summit of G-20 leaders in Germany was so dominated by personality politics (particularly the meeting between Donald J. Trump and Vladimir Putin) that a highly consequential policy change by the United States risked going overlooked: the president’s pledge to spend an additional $639 million to fight famines in Africa and the Middle East. Without the immediate release of those funds, an estimated 400,000 to 600,000 children will probably die of starvation in the next four months, according to David Beasley, the head of the United Nations’ World Food Program and former Republican governor of South Carolina.

It is a welcome change in the Trump administration’s policy and frequently isolationist rhetoric. In March the White House released a budget proposal that cut foreign aid over all by one-third. This reduction, unlikely to be approved by Congress, would be unconscionable at a time when the world is facing the unprecedented threat of four famines at once. In Somalia, Yemen, South Sudan and eastern Nigeria over 30 million people are estimated to be at risk of starvation if the global community does not act now.

What makes these four famines especially tragic is that they are, for the most part, man-made. Periods of mass starvation due to drought or natural disasters have plagued humanity since the dawn of agriculture. But today, famine is a byproduct and at times a tool of war. In February the United Nations officially declared a famine in parts of South Sudan, which has been torn apart by ethnic strife and civil war since its founding in 2011. To make matters worse, aid workers trying to bring relief to areas affected by war and famine have been the target of attacks by fighters on both sides of the conflict. The United Nations alleges that the government has prevented its convoys from entering rebel-held areas.

Meanwhile, Somalia, where the Islamist militant group al-Shabaab controls much of the country, is threatened with its second famine in five years. Six million people are in need of food aid. In eastern Nigeria, fighting between the government and the Islamist insurgent group Boko Haram has decimated the agriculture sector, leaving 4.8 million “severely food-insecure,” according to the U.N. Office for the Coordination of Humanitarian Affairs. Finally, in Yemen, a civil war between the Saudi Arabia-backed government and Iran-backed Houthi rebels has created a humanitarian disaster. Saudi Arabia, the world’s biggest purchaser of military weapons from the United States, has imposed a blockade on the country and bombed transportation and agricultural infrastructure; an estimated seven million people face starvation.

The Trump administration should be commended for stepping up in the face of these crises and increasing what has been called “soft power”—the promotion of American values and ideals through humanitarian aid rather than military might alone. Global leadership, however, requires more than a one-time donation to solve an obvious and visible crisis. Climate change is expected to make drought and famine more common in the countries least able to cope with its effects. If Mr. Trump is unwilling to join, much less lead, the world community in farsighted efforts to protect the planet, he can expect to spend many millions more fighting the hunger and displacement sparked by a changing climate.

This article appears in July 242017.