Billionaires Bill and Melinda Gates issued their annual letter on Tuesday, revealing global philanthropic accomplishments in the past year and outlining what they hoped to accomplish this year, including helping people understand “what it will take to stop climate change.”

Without calling out the Green New Deal resolution by name, Bill Gates said it was “not realistic” to think the entire economy and infrastructure could be transformed in a few years.

After naming five “grand challenges in climate change” — buildings, manufacturing, agriculture, transportation, and electricity generation — he slammed the core ideas behind Rep. Alexandria Ocasio-Cortez’s (D-NY) signature Green New Deal.

“It’s not realistic to think that people will simply stop using fertilizer, running cargo ships, building offices, or flying airplanes,” Bill Gates wrote in the letter. “Nor is it fair to ask developing countries to curtail their growth for the sake of everyone else.”

“For example, for many people in low- and middle-income countries, cattle are an essential source of income and nutrients,” he wrote, adding that the best approach would be to “invest in innovation” so that things could continue “without destroying the climate.”

“We need breakthrough inventions in each of the grand challenges,” Bill Gates wrote. He did also say cows were a problem when it came to climate change.

“Agriculture accounts for 24 percent of greenhouse gases. That includes cattle, which give off methane when they belch and pass gas,” he wrote. “(A personal surprise for me: I never thought I’d be writing seriously about bovine flatulence.)”

In his remarks, Bill Gates blamed the media for not talking about climate change, including cows, enough.

“We need to do a much better job of informing people about the challenges,” Bill Gates wrote. “It would help if media coverage matched the breadth of the problem.”

“Solar panels are great, but we should be hearing about trucks, cement, and cow farts too,” he wrote.

The letter also covered other areas where they were making a difference with their money, including in Africa where the “right investments will unlock the continent’s enormous potential.”

Reducing premature births, ending gender discrimination in data collection — “data can be sexist” — and continuing to study poverty, including the “link between poverty and mass incarceration,” were all on the Gates’ to-do list.

The letter also addressed how toilets could save lives, how software is replacing textbooks, and how women are empowered with cell phones.

“In other words, women are not only using their mobile phones to access services and opportunities,” Melinda Gates wrote. “They’re using them to change social norms and challenge the power structures that perpetuate gender inequality.”

The Gates ended their letter by saying that rather than “feeling overwhelmed by negative headlines” they were taking action and remaining optimistic.

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