Stanford University
Oil derrick and wind turbines

Stanford energy expert discusses UN climate report

Energy expert Inês Azevedo, a lead author of the energy chapter in the United Nations’ new report on climate mitigation, discusses the assessment and changes necessary to keep global warming below 2 degrees Celsius.

BY Josie Garthwaite
ClockApril 06, 2022

The world can still avoid the most disastrous consequences of global warming, according to the United Nations’ latest climate change report, if societies make deep and immediate cuts to emissions across all sectors.

“We have the technologies needed to have net-zero energy systems. What we are lacking is time,” said Inês Azevedo, one of the lead authors of the report’s chapter on energy systems, which finds global warming cannot be limited to well below 2°C (3.6°F) without dramatic reductions in oil, gas and coal use and a rapid increase in production from low- and zero-carbon sources, in tandem with widespread electrification and energy efficiency gains.

Azevedo and coauthors of the energy systems chapter describe continued investments in fossil fuel infrastructure – particularly coal-fired electricity without carbon capture and storage (CCS) – as “inconsistent with limiting warming to well below 2°C,” the ambition of the 2015 Paris Climate Agreement. Achieving that goal will effectively turn fossil fuel infrastructure and unburned coal, oil and gas into “stranded assets,” meaning their financial value all but disappears – with economic impacts amounting to trillions of dollars.

However, the energy transition will also create opportunities as investments are reallocated away from fossil fuels and toward renewables, carbon capture and storage, electricity networks and storage, efficiency improvements and nuclear power. “The electricity produced by solar and wind is now cheaper than the fossil fuel alternatives in several locations, and the cost of other needed technologies, such as storage and electric vehicles, is decreasing rapidly and now cost competitive,” Azevedo said. “But a massive amount of investment is needed in new infrastructure to make our energy system low-carbon, while ensuring that the technology and tools are in place to make sure it remains reliable and resilient.”

Azevedo is an expert in assessing how energy systems are likely to evolve over time, taking into account the technologies that can address future energy needs and the decision-making processes followed by various actors in the economy. She is an associate professor of energy resources engineering at Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth) and a senior fellow at Stanford Woods Institute for the Environment. She is also a senior fellow at the Precourt Institute for Energy and co-director of Precourt’s Bits & Watts Initiative. Here, she discusses the findings of the new report.

What is the most important message to take away from this report, broadly, and from the energy chapter, specifically?

Time is running out to be able to avoid the consequences of warming higher than 2°C. We need to deploy a portfolio of technologies but it is imperative to also have sustained policies for the needed emissions reductions to be achieved.

We have the technologies needed to decarbonize a large portion of the energy system. In some cases the low-carbon technologies also correspond to the cheapest one – for example, electricity generated by wind and solar is now cheaper than fossil fuels in several places.

What do the findings of this report tell us about how the nation and the world’s energy systems will need to change to limit global warming to 2°C or below?

Globally, the report finds that limiting warming to well below 2°C would require that by 2030, carbon dioxide emissions are reduced by one-third to one-half of the current emissions levels. Decreasing coal generation without CCS would constitute the bulk of emissions reductions by 2030, with coal use falling drastically by 67 percent to 82 percent in 2030 in scenarios limiting warming to 1.5°C.

Coal would need to be virtually eliminated in the following decades. Natural gas can still be used in 2030 and usage would need to peak sometime between 2035 and 2050, for electricity generation and industrial purposes. The use of natural gas would need to be reduced up to one-third by 2050. For oil, the consumption would need to decline substantially in the long term, but it could continue to be used through mid-century even if warming is limited to 2°C or less. If we are aiming for 1.5 or less, then the oil consumption would need to start decreasing immediately.

Carbon removal may be needed, and we should invest in research and development to understand its viability, but the level of emissions reductions and time where carbon removal would need to be started varies widely across scenarios.

What will limiting global warming to 1.5°C or 2°C require of us on the demand side? What must change in the way energy is used – both on a global scale and in high energy-consuming countries like the United States?

On the demand side, there will be important contributions from electrifying end-uses that will be sustained by a low-carbon grid. Electric vehicles, using electricity for cooking, heating and water heating are some of the steps that will help. In the transportation sector, transportation modes must change where possible to walking, biking, public transit. On the buildings side, energy-efficient buildings and insulation retrofits are needed. The way we produce food and the type of food may require changes. However, I want to stress that while the demand side factors can help, there is no way we can get to the level of emissions reductions needed without changing the supply side of this equation.

What, if anything, gives you hope or confidence that global warming will be limited to 1.5°C? Or 2°C?

It gives me hope to know that we do have the technologies and policy mechanisms to allow us to limit the warming to well below 2°C. However, whether we will actually do it or not keeps me up at night – we should have started making progress decades ago.

Fort Martin Power Station
Fort Martin Power Station burns coal beside the Monongahela River in Maidsville, West Virginia. (Image credit: Steve Heap / Shutterstock)

Destructive thresholds

The UN panel of hundreds of leading experts in climate science, energy, social science, policy and economics concluded annual greenhouse gas emissions must peak before 2025 and fall by 43 percent by 2030 to limit warming to 1.5 C above pre-industrial levels. Low-carbon energy sources such as wind, solar, hydropower and nuclear will need to provide as much as 97 percent of global electricity by 2050 to keep 2 C within reach.

A vast body of research points to 1.5 and 2 degrees Celsius as destructive thresholds beyond which climate impacts including extreme heat waves, coastal floods, crop failures, intense droughts and extinctions are likely to become more severe and widespread. Already, the world has warmed by 1.2 C since pre-industrial times.

Media Contacts

Josie Garthwaite

School of Earth, Energy & Environmental Sciences

(650) 497-0947,

Inês Azevedo

School of Earth, Energy & Environmental Sciences

(650) 497-0818,

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