Global warming is making it harder and more expensive to feed the world, according to a new United Nations report on climate change.
More than 300 authors produced the 32-volume report, which warns of dire consequences if the world fails to act.
"The message is very, very stark: unless we cut our greenhouse gas emissions very rapidly we will be inflicting disaster on ourselves and generations to come," Andy Atkins, executive director of the environmental group Friends of the Earth, said.
Bob Ward, a policy director at the London School of Economics, explained, "The report spells out that there are going to be potentially huge, catastrophic impacts and that's why it says we need to reduce emissions in the long term."
A prestigious group of scientists, some Nobel-prize winning, created the report.
Still, not everyone in the scientific community agrees with its findings -- including one of the authors, Richard Tol, who believes the conclusions are too alarmist.
"What the report, for instance, forgets to say is that even though climate change may reduce crop yields by 2 percent per decade, at the same time crop yields are going up by 10, 15, 20 percent per decade due to technological change," Tol, an economist with the University of Sussex, explained.
"So, it's not the case that climate change will cause life-threatening famine; instead, climate change will mean that crop yields will go up more slowly," he said.
A non-governmental group of scientists, backed by the libertarian think tank, The Heartland Institute, is also pushing back.
The institute maintains that higher carbon dioxide concentrations and rising temperatures are causing "no harm to the global environment or to human health."
For years, some scientists have warned that climate change advocates have a radical agenda -- even comparing them to religious cults.
Others simply note that power, prestige and money are all part of the debate.
"There is, of course, a totally different agenda for the people who are pushing global warming. That's all about money, about making hundreds of billions of dollars for certain individuals who are pushing the whole thing," Don Easterbrook, a geology professor emeritus at Western Washington University, said.
Patrick Michaels, senior fellow in environmental studies at the Cato Institute, agreed.
"I'm not convinced that there are that many scientists who view this as this apocalyptic, end-of-world issue," he said in 2011. "But that gets a lot of coverage."
"If I tell you the world is going to end, I'll get on TV," he continued. "If I tell you it's not, I probably won't."