Consequences of Climate Change: California Grassland To Become Less Productive Due to Warmer Climate

Previous research claims that the higher carbon dioxide concentration in the atmosphere and warmer temperatures could help increase net grassland productivity in California. However, a new study revealed that it might be the opposite.

The study, published in the journal Proceedings in the National Academy of Sciences, suggests that substantial increase in temperature and precipitation above average conditions from the past 40 years could lessen the agricultural productivity of California grasslands.

"There's been some hope that changing climate conditions would lead to increased productivity of grasses and other plants that draw down carbon dioxide from the atmosphere," explained Kai Zhu, a global ecologist and data scientist at Rice University and lead author of the study, in a statement. "In northern California, it was hypothesized that net grassland productivity might increase under the warmer, wetter conditions that are predicted by most long-term climate models. Our evidence disproves that idea."

For the study, the researchers analyzed data from the Jasper Ridge Global Change Experiment, a continuous experiment, which started in 1998, involving 136 test plots that simulate different climate change scenarios and their effects on agricultural productivity.

The researchers discovered that the average conditions in the past 40 years is the near optimal for grass productivity. Any significant deviation toward warmer or wetter conditions could lessen the land's productivity.

Furthermore, the researchers also debunked popular belief that higher levels of carbon dioxide in the atmosphere are god for the plants. The researchers noted no significant improvement in grass productivity in plots that have almost twice the amount of carbon dioxide present today in the atmosphere.

"The nonresponse to CO₂ is as important as any of our other findings," Zue said in a press release. "That finding may surprise people because a lot have said that if you have more CO₂ in the atmosphere, you'll get better growth because CO₂ is a resource for plants. That's a popular hypothesis."