Climate scientists, says a climate scientist, must veer away from their "track record of mistaken conservatism." Instead, he says, they should sound the alarm about how vulnerable we have already become to potentially catastrophic events as a result of climate change.

For example, says Wolfgang Knorr in an article on the website The Conversation, extreme weather events resulting from climate change could put our global food system at risk. If drought strikes several countries at once, our global food chains might collapse over the next decade or two.

Knorr is a senior research scientist in physical geography and ecosystem science at Lund University in Lund, Sweden. The Conversation presents news and views from members of the world's academic and research communities. It operates under the slogan "academic rigor, journalistic flair."

"Scientists are by nature conservative," Knorr says. "Usually, this is good practice. But it has caused climate scientists to consistently underestimate both the speed at which the climate is destabilising and the severity of the threat it poses."

As a result, he suggests, communities and politicians worldwide have not taken the actions necessary to even slow the growth of carbon dioxide emissions from human activities, let alone start to reduce emissions.

Graph from Wolfgang Knorr

"Since the middle of the 19th century, CO2 emissions from human activities have been growing exponentially, on average by 1.65% per year since 1850," Knorr says.

"Our painful sluggishness to act is not the fault of scientists," he says. "But the crisis is now more urgent than ever, and our current approach to it is starting to make us part of the problem."

Activism can actually make a positive difference in attitudes about climate change, according to another article on The Conversation by Nathaniel Geiger, assistant professor of communication science at Indiana University.

Geiger and colleagues surveyed US public opinion before and after the People's Climate March, which brought thousands of climate activists into the streets of Washington, DC, and other cities around the world on two consecutive weekends in April 2017.

The researchers published their findings in a February 27, 2019, article in the journal Frontiers in Communication.

Respondents reported less pessimism that people could come together to fix big problems after the march. Perhaps surprisingly, the largest swing toward optimism came from people who got their news primarily from conservative media. Before the march, 60% of them agreed at least somewhat that "people are too selfish to cooperate and to fix big problems." After the march, only 45% agreed.

Comparable figures were 37% before and 31% after among consumers of centrist media, and 45% before and 40% after among consumers of liberal media.

Survey respondents as a whole also reported viewing climate activists as less aggressive, less dictatorial, and less arrogant after the march.