In an interview with the Guardian ahead of the UN General Assembly, Gates said that the Bill & Melinda Gates Foundation and others like it will not be able to cover the funding gaps left by President Trump, who has proposed cuts to U.S. aid budgets. He explained that “there’s no way to balance a cut in a rich country’s generosity.”

Back in April, Trump announced his 2018 budget proposal, which included a 31% cut to the international affairs budget. Cuts would affect funding of international institutions like the UN and World Bank, but more significantly would drastically decrease overseas development assistance. The U.S. is the world’s largest global aid donor, yet as it stands, the $30 billion U.S. foreign aid budget is less than 1% of the $3.8 trillion federal budget.

According to new research published by the Gates Foundation and the Institute for Health Metrics and Evaluation, proposed budget cuts have the potential to jeopardize global progress in combating global poverty and disease. Trump’s budget for global health programs included a 24% cut to efforts to combat HIV/AIDS, tuberculosis and malaria. And the research shows that with these cuts, five million more deaths could be expected from AIDS alone by 2030.

Founded in 2000, the Gates Foundation is the world’s largest. Gates himself recently made a $4.6 billion donation to his foundation, which spends more than $3 billion each year on development assistance. However, this is a fraction of the U.S. aid budget, and constitutes an even smaller proportion of the global aid budget, which stands at $143 billion.

Gates told the Guardian that his foundation doesn’t “have some special stash that we keep in case some government is less generous. We’re spending at our maximum capacity because we know that every $1,000 we spend, we’re saving an additional life. So if net, from all governments as a whole, you get big cuts, there’s no other sector that has fair capacity to step up.”