A humanitarian catastrophe is underway in Mozambique, Malawi, and Zimbabwe as the full scale of devastation from Cyclone Idai becomes more clear.

The World Meteorological Organization said Idai, which made landfall five days ago, could become the worst tropical cyclone on record in the Southern Hemisphere. Mozambique President Filipe Nyusi fears that 1,000 people may have died in his country alone. The U.N.’s World Food Program called it “a major humanitarian emergency that is getting bigger by the hour.”

The initial post-storm reports are harrowing: 90 percent of Beira, Mozambique — a city of more than 500,000 people — has been destroyed by floodwaters. The first aid workers to reach the hardest-hit areas found people clinging to trees and rooftops, awaiting rescue, with waters still rising. Social media posts from Zimbabwe showed people swept away on flooded roads and aerial images in Mozambique showed countless homes underwater. Nearly 3 million people have been affected across the region, one of the poorest in the world.

Cyclone Idai is not a natural disaster; the storm was made worse by climate change, centuries of colonialism, and continuing international injustices.

Grist thanks its sponsors. Become one.

There are at least three major ways that the Mozambique floods are related to climate change: First, a warmer atmosphere holds more water vapor, which makes rainfall more intense. Idai produced more than two feet of rainfall in parts of the region — nearly a year’s worth in just a few days. Second, the region had been suffering from a severe drought in recent years in line with climate projections of overall drying in the region, hardening the soil and enhancing runoff. Third, sea levels are about a foot higher than a century ago, which worsens the effect of coastal flooding farther inland.

“Cyclone Idai is a clear demonstration of the exposure and vulnerability of many low-lying cities and towns to sea-level rise as the impact of climate change continues to influence and disrupt normal weather patterns,” said Mami Mizutori, the U.N.’s Special Representative for Disaster Risk Reduction, on Monday.

Grist thanks its sponsors. Become one.

What’s worse, after years of drought, food supplies were already running low, with disproportionate impacts on children — the rates of child labor and forced marriages had been edging upwards. With hundreds of square miles of farmland now underwater, there is slim hope for a quick recovery.

It’s difficult for those of us in wealthier countries to imagine a disaster like this because we have built a society that is, in part, designed to protect us from extreme weather. Cyclone Idai is a humanitarian crisis that once again lays bare the fundamental injustice of climate change.

During four centuries of colonial rule, Mozambique was used as a source of slaves, mines, and plantation agriculture. The nation gained independence from Portugal in 1975 after a 10-year long revolutionary war. A devastating 15-year civil war followed shortly thereafter. But the war’s legacy lasts. Mozambique ranks 180th out of 189 countries in the U.N.’s Human Development Index — a measure of life expectancy, education, and economic prosperity — the lowest of any cyclone-prone country in the world.

Decades of dictatorship and unrest followed British colonization in neighboring Zimbabwe and Malawi. All three countries are among the poorest in the world.

And climate change makes it even more difficult to rebound: In his address to world leaders at the Paris climate summit in 2015, then-Prime Minister of Mozambique Carlos Agostinho do Rosario spoke of his country’s flood risk: “These weather phenomena affect the government’s efforts to meet national priorities, especially food security, that are critical to poverty reduction.”

For decades, folks in the global South have called for climate reparations — a large-scale transfer of wealth to help poorer countries adapt to climate change.

We had some tenuously promising signs during Paris Agreement negotiations. Rich countries committed to ramping up aid to $100 billion per year in restorative climate funding by 2020. We’re one year out, and barely 10 percent of the initial funds have been raised. Before he left office, Obama committed the United States, historically responsible for about a quarter of all human-caused greenhouse gases in the atmosphere, to $3 billion — just $9.41 per American. Now, of course, Trump wants to leave the agreement entirely.

Wealthy countries must take responsibility for the unimaginable suffering we are inflicting. Today, as seen with Cyclone Idai, those most affected by climate change are those who have done the least to create the problem.

And judging by the aftermath of Hurricane Maria in Puerto Rico, the humanitarian disaster is just beginning. The international community has a responsibility to immediately aid Mozambique and the rest of the region with food, water, shelter, and medicine — now.

And it can’t stop there. We owe it to the people on the frontlines of climate change to break the cycle of extreme poverty we’ve helped perpetuate.

Cyclone Idai should be a sobering reminder that in many parts of the world, people don’t have the luxury of ignoring climate change. Its destruction is already here.