UW professor breaks down latest UN climate change report

MADISON, Wis. — When it comes to the climate crisis, Gregory Nemet has good news and bad news.

“The climate problem is getting worse,” said Nemet, a professor at UW-Madison’s La Follette School of Public Affairs. “But the solutions are improving.”


What do you want to know

  • The UW’s Gregory Nemet, who worked on the latest IPCC report, said the findings spur us to act quickly on climate change
  • Report calls on countries to achieve net zero emissions over the next 30 years to limit global warming
  • Clean energy has made great strides and is now a cheap alternative in our energy transition
  • There is hope for climate mitigation, but more action is needed to secure the future, Nemet said

It was a great conclusion of a recently published report by the United Nations Intergovernmental Panel on Climate Change. Nemet was one of the main authors of the IPCC report, which led scientists around the world to examine our options for mitigating global warming.

The report points out that if we are to contain climate change in the years to come, it’s now or never.

“We are at a crossroads”, Hoesung Lee, chairman of the IPCC said in a press release. “The decisions we make now can ensure a livable future.”

But the findings also offer some hope for how we can contain the climate crisis, Nemet explained. Here, we break down some of his takeaways from the “interesting and intense process” of working on the report.

We must reduce greenhouse gas emissions – and do it quickly

According to the latest report, global greenhouse gas emissions have steadily increased in recent years and in the 2010s reached their highest levels in human history.

And we are already seeing the effects of the climate crisis – from forest fires to rising seas, from violent storms to mass extinctions, like previous IPCC research has highlighted.

“The bad news is, yes, this climate damage is happening. They’re going to get more frequent unless we really make a big change,” Nemet said. “And if you look at the last 10 years, we haven’t made the changes that we needed.”

To achieve the overall goal of limit warming to 1.5°C, greenhouse gas emissions must be down by 2025, according to the report. And by the start of the 2050s, the world must reach net zero in its carbon emissions, the researchers found.

One problem with greenhouse gases is that they stay in the atmosphere for a long time, even compared to other pollutants, Nemet explained. Once the carbon dioxide is released, it can stay in the atmosphere for centuries.

So the emissions we’ve already sent into the atmosphere aren’t going away any time soon. And that doesn’t leave us much leeway to stay below the 1.5C tipping point, Nemet explained.

“We’re already at 1.1,” he said. “There just isn’t a lot of room to keep emitting greenhouse gases into the atmosphere if we’re going to be climate secure.”

Clean energy has made progress

However, the conclusions of the IPCC are not all pessimistic.

“On the other hand, on the more optimistic side, there are clear signs of progress that were not true when the last report came out in 2014,” Nemet said.

On the one hand, clean energy has become much cheaper in recent years, Nemet pointed out. Since 2010, solar energy costs have fallen by 85% and wind energy costs by 55%, according to the report.

Nemet, who wrote a book on the economics of solar energy, said that growing markets have helped bring down these energy costs and make solar energy the cheapest source of energy we have. These economies of scale – where “the more you make, the less it costs to make the next one” – can also help lower the costs of other clean energy.

The report also highlighted the role of carbon removal technologies that can capture greenhouse gases from the atmosphere. These options are important because some sectors — such as aviation, industry and agriculture — will be difficult to achieve zero emissions, Nemet said.

“If we want to have shows from these places, we have to balance them somewhere else with something negative,” he said.

But removing carbon cannot be the only solution. “We need to do both,” he said: reduce the emissions we send into the atmosphere and suck the carbon that’s already there.

We have options to reduce global emissions

Reversing the tide of climate change will mean major transitions on many levels, the report points out.

“We need behavior change,” Nemet said. “We need people to start making different choices about where they live, how they live, how they move, what they eat.”

In addition to getting our energy from clean sources, we can also work to use less energy overall, Nemet said. This can mean personal choices like eating plant-based diets, using shared transportation, and downsizing smaller living spaces.

Many of these changes are not only good for the planet, they are also good for people’s well-being, according to the report.

But the report insists on the need to act beyond individual choices.

To limit global warming, entire industries – from construction to agriculture to transportation – must reduce their dependence on fossil fuels, the report points out. This could involve building with more sustainable materials, increasing green spaces in cities, and adding electric vehicle infrastructure.

And governments will need to drastically increase their investments to keep warming below 1.5°C, according to the report. Policies and finance to mitigate climate change have been patchy so far, the report says, but we need more ambitious action going forward.

“Everything needs to be cleaned up, but we have the tools available,” Nemet said. “And so, it’s really about investing, making the changes necessary to make things move faster than they have been.”

There are reasons for hope in our climate future

Although global emissions have continued to rise, the IPCC report found that 18 countries have been able to reduce their greenhouse gas emissions for a decade or more.

These are long-term declines – not just blips of unusual circumstances like, say, a pandemic, said Nemet. And this is another encouraging change from the previous report in 2014.

“We wouldn’t have said eight years ago that the cost of renewables is coming down and cheaper than fossil fuels. Now we say that,” Nemet said. “We couldn’t have said that many countries actually reduced their emissions.”

Now we also have to bring the rest of the countries to decline, and do everything much faster, he said.

In this way, the IPCC report leaves us with a great challenge. The timeline for global emissions reductions is rapid and will require major changes to occur immediately.

But Nemet said that looking at the progress we have already made and seeing the growing number of people dedicated to fighting climate change, he hopes we can achieve this transformation.

“People don’t appreciate everything that really happened and is happening,” Nemet said. “So it’s really very optimistic.”

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