I’m actually not sure the Al Jazeera writer has the sources, as this piece is done by interviewing the scientists. The journalist simply asked the scientists an

I’m actually not sure the Al Jazeera writer has the sources, as this piece is done by interviewing the scientists. The journalist simply asked the scientists and reported on what they said. Surely the journalist could ask the scientists for sources, and maybe they should have, and maybe they did but the scientist didn’t have them at hand at that exact moment. But if you are interested, here is the tweet in question: https://twitter.com/KHayhoe/status/1640915926152298497 https://twitter.com/KHayhoe/status/1640915926152298497 In journalism it is often more important to find sources which back each other up, rather then finding original research. In this case the journalist interviews a few scientists that all tell a similar story. I think the journalist here is simply doing what they have been trained to do.