The message from scientists last week during a climate change conference was clear and unequivocal: the need to further reduce greenhouse gases is critical and changes must be implemented without delay.

The Our Common Future Under Climate Change conference was hosted by the United Nations Educational, Scientific and Cultural Organization (UNESCO). Attended by almost 2,000 scientists and academics, representing almost 100 countries, organizers called it the largest scientific forum to gather in preparation for the U.N.’s Climate Change Conference, scheduled this fall.

The objective of the conference was to discuss the many facets of climate change and to explore different mitigation strategies. Average global temperatures are used as the yardstick for progress, and are directly tied to carbon emissions.

In his keynote speech, Secretary-General of the United Nations Ban Ki-moon said that steeper emissions reductions are needed to prevent further temperature increases.

“At the United Nations climate talks in 2010, governments committed to a maximum temperature rise of 2 degrees [Celsius] above pre-industrial levels,” said Ban. “However, the [Intergovernmental Panel on Climate Change] tells us that we are heading towards average global warming of 5-6 degrees.

“It is already clear that current [Intended Nationally Determined Contributions] will not be sufficient to meet the 2 degree target. Clearly, strong action still needs to be taken.”

In order to meet the goal of a 2-degree increase by the end of the 21st century, said the conference’s outcome statement, current carbon dioxide levels must be lowered, and carbon emissions must be zero, or even negative.

“Continued high emissions of heat-trapping gases increase the risk of impacts that are severe, pervasive, and irreversible. Risks for people, economies, and ecosystems are all much greater in a world of continued high emissions, with warming by the end of the century potentially reaching 4 degrees or more above preindustrial levels, than in a world of ambitious mitigation,” said UNESCO.

Successful mitigation solutions are available and will be “economically feasible” if they are implemented right now, according to UNESCO.

“Delaying deep emissions cuts, waiting on the sidelines by some countries, or excluding particular clean-energy technologies all increase costs and complexity. Cost-effective mitigation pathways to limit warming to 2 degrees require reducing emissions of greenhouse gases by 40-70 percent below current levels by 2050,” said the organization.

Joseph Stiglitz, Nobel laureate and economist with Colombia University, suggested a global tax on carbon as an effective way to encourage emission reductions.

“This reflects the basic economic principle: that it’s better to tax bad things than good things,” said Stiglitz.

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Policy changes that encourage alternatively fueled vehicles is also key, according to several presenters at the conference in Paris.

Plug-in electric vehicles (PEVs) “could reduce greenhouse gas emissions in the transportation sector, which currently accounts for 28 percent of Canada’s emissions,” said John Axsen, an assistant professor at Simon Fraser University who studies sustainable energy systems.

“The role of strong climate policy, such as carbon pricing or regulations such as a Zero-Emissions Vehicle mandate (as implemented in California and several other U.S. states)” is the most important way to encourage widespread adoption of PEVs, said Axsen. “Without such supply-focused policies in Canada, it is unlikely that a substantial transition to electric mobility will occur in the coming decades.”

A full catalog of the conference’s 2,200 scientific papers is available online. And in November, Paris will once again host an international conference on climate change. But this time the outcome will include new global standards intended to prevent temperatures from climbing even higher.


Photo: Twitter screenshot via @ClimatParis2015