The fact that plants need CO2 to grow is certainly not news for climate scientists, or really anyone with even the most elementree knowledge of biology, so the fact that an increase in CO2 levels can help plants grow is by no means news either. Known as the CO2 fertilization effect, it has been incorporated into climate models for only slightly longer than fossil-funded deniers have claimed it’s been ignored. See, for example, the 1992 coal-funded video, Greening of Planet Earth, or the quite similar 2013 talk by Matt Ridley about Greening the Planet.
Every time new research quantifies some aspect of an increase in vegetation as CO2 levels have increased, it sweeps through the deniersphere like a fire through a drought-stricken forest. In the past, they’ve been assisted by mainstream media, which regularly failed to provide important context, namely that the fertilization effect diminishes over time, nitrogen availability, not CO2, is what limits growth, and that other impacts of climate change will eventually overwhelm the fertilization.
There’s a new study in Nature that has found a significant increase in plant cover over the past few decades, caused mainly by the increase in carbon dioxide. No doubt aware of how much denial has been rooted in the CO2 fertilization effect, the press release wisely included a quote from one of the authors pushing back on the contrarian framing, even calling out Matt Ridley and Rupert Murdoch by name. This allowed BBC’s Roger Harrabin to write a story that nips the denier argument in the bud by stating clearly that CO2’s negatives will outweigh this positive. In addition, Professor Richard Betts has a comprehensive post at Carbon Brief about CO2 fertilization and climate change that fells this longstanding denier meme.
Regardless, since they're pining for whatever meager evidence they can get, deniers just couldn’t leaf this study alone.
So while the study’s not exactly groundbreaking in subject, it is an interesting approach: combining computer modeling with satellite images to measure photosynthesis through model and photo synthesis.