Skip to main content Skip to secondary navigation
Main content start

A roadmap to reducing greenhouse gas emissions 50 percent by 2030

An international group of experts, including Stanford Earth system scientist Rob Jackson, has published a roadmap of the most viable solutions for slashing greenhouse gas emissions globally by 2030. 

Greenery with globe graphic
(Image credit: Romolo Tavani/Getty Images)

In advance of the 2019 United Nations Climate Summit in New York City Sept. 23, an international group of experts, including Stanford Earth system scientist Rob Jackson, has published a roadmap of the most viable solutions for slashing greenhouse gas emissions globally by 2030. The 36 solutions – ranging from solar and wind to electric bikes, commercial shipping and reduced red meat consumption – have the potential to scale rapidly. Jackson will also speak at a summit side event unveiling a landmark World Meteorological Organization report he coauthored on gaps in progress toward internationally agreed upon climate targets, and he will brief Hungarian President János Áder on climate-related issues. 

“Cut emissions from coal and cars and save thousands of American lives. Who wouldn’t support that?” said Jackson, the Michelle and Kevin Douglas Provostial Professor in the School of Earth, Energy & Environmental Sciences. “If the federal government won’t act, our cities and states will. I’m looking for new climate pledges across  the U.S.”

Stabilizing Earth’s temperature to significantly reduce risks to societies now requires greenhouse gas emissions to reach net zero by 2050. This translates to cutting greenhouse gases by about 50% by 2030 alongside significant removal of carbon dioxide from the atmosphere. 


Some takeaways of the roadmap report:

  • Low cost solar, wind, and battery technologies are on profitable, exponential trajectories that if sustained, will be enough to halve emissions from electricity generation by 2030.
  • Electric vehicle growth has the potential to reach a 90% market share by 2030 if sustained, but only if strong policies support this direction.
  • Digital technology remains a wild card. It could support a rapid transformation of our economic systems or could drive emissions higher.
  • Four drivers for rapid transformation are converging: growing social movements, the rise in the number of countries discussing a target of net-zero by 2050, the economic logic of rapid transition and the speed of technological innovation.


“While this scale of transformation is unprecedented, the speed is not,” said report author Johan Rockström, director of the Potsdam Institute for Climate Impact Research, Germany and co-chair of Future Earth, an international research programme. “This is now a race against time, but businesses and even entire industries have made many significant transitions in less than 10 years,” he said.  

Christiana Figueres, former head of the United Nations Framework Convention on Climate Change, and Convenor of Mission 2020, a partner organization in the roadmap, said, “I see all evidence that social and economic tipping points are aligning. We can now say the next decade has the potential to see the fastest economic transition in history. The 2019 Exponential Roadmap is an excellent guide for the necessary journey to net-zero emissions.” 

Manuel Pugal-Vidal, leader of the climate and energy practice at WWF, a partner of the report said, “Governments must introduce national targets to reach net-zero emissions by 2050 with targets to cut emissions 50% by 2030. Immediate removal of fossil-fuel subsidies is a priority. Yet policies must be equitable and fair or risk failure.”

“Developed nations with significant historic emissions also have a responsibility to reduce emissions faster. Cities and states – not only countries – will also be important change makers,” he said.

The green economy’s taking off like a jet, but emissions are still climbing. We need stronger green policies and low-carbon breakthroughs.

 — Rob Jackson, Michelle and Kevin Douglas Provostial Professor, Earth System Science

The report highlights four approaching tipping points that combined will accelerate the transformation: 

  • Growing social movements (for example, Fridays for Future) changing the public conversation in parallel with companies and cities stepping up climate action.
  • Emerging political support for more ambitious targets, for example countries such as the UK, France, Norway and Sweden adopting laws to reach net-zero emissions by 2050 or earlier.
  • Solar and wind energy have reached a tipping point and are now cheaper than fossil fuels in many places. Tumbling costs and rapid innovation of low-emissions technology including battery storage and electric vehicles makes a very rapid transformation almost inevitable. 
  • Digitalisation and global communications allow more rapid scaling than previous transformations. 

“This roadmap uniquely focuses on three things. The immediate priorities – reaching peak emissions in 2020 and racing to cut emissions in half by 2030. How we scale the new solutions exponentially. And how we need to think in terms of systems transformation of the whole economy,” said Johan Falk, an expert in exponential strategies, co-lead author and a fellow at Stockholm Resilience Centre and Future Earth, Sweden. 

The authors see the circular economy as one of the most significant ways for industries to reduce emissions. “An immediate priority is to build the policy environment for a circular economy. This could provide half of the emissions reductions we need by 2030 from key industry,” says Falk.  

The report is a collaboration between academia, business, and civil society groups solutions in six sectors: energy, industry, transport, buildings, food consumption, and nature-based solutions. In the energy sector, the authors conclude the world has reached a tipping point. 

“The green economy’s taking off like a jet, but emissions are still climbing,” Jackson said. “We need stronger green policies and low-carbon breakthroughs.”

In transport, electric vehicles have the potential to reach a 90% market share by 2030, but only if strong policies support this direction. Even shipping is able to reduce emissions 50% with modifications to routes, speed, and fuel types. The world’s largest container shipping company, Maersk, for example, has now committed to reach net-zero emissions by 2050. 

The new roadmap includes findings from several major academic assessments on food system transformation that have been published in the past year, including the EAT-Lancet Commission on Healthy Diets from Sustainable Food Systems and the IPCC climate change and land report. 

“Food and agriculture is the dark horse in the fight against climate change. It may be the hardest sector to rapidly halve emissions,” said Brent Loken from the EAT Foundation and lead author of the chapters on food consumption and nature-based solutions.

It will require a dietary transition from high consumption of red meat and ultra-processed foods to a more healthy diet with plenty of fruit, legumes and vegetables. In addition, the roll out globally of more sustainable farming practices. Barriers include poor land-use planning, contradictory subsidies, focus on quick profits, regulatory barriers, insufficient funding, lack of knowledge, and vested interests could slow progress.

But avoiding deforestation, in addition to reforestation and improved land management is a significant opportunity to reduce and sequester greenhouse gases in the atmosphere. The authors estimate nature-based solutions could be used to sequester around 9 billion tons of CO2 annually by 2030. 

The building sector also requires profound changes. Reducing greenhouse gases 50% can be delivered through greater efficiencies in use of building space alongside energy efficient refurbishment and net zero-emission construction.

The second in its series, the 2019 Exponential Roadmap is complemented with a high-ambition narrative, Meeting the 1.5°C Ambition, that presents why the world must aim to hold global average temperature increase to just 1.5°C. Each new roadmap updates solutions that have proven potential to scale and charts progress towards exponential scaling, using exponential strategies needed to cut emissions 50 percent by 2030 or earlier, then doing it again by 2040 and again by 2050. The first was published in 2018 at the Global Climate Action Summit. 

Since the first roadmap, the Intergovernmental Panel on Climate Change (IPCC) published its special report on the impacts of global warming of 1.5 °C above pre-industrial levels. The report concluded that the economic and humanitarian risks of a 2°C world are significantly higher than one at 1.5°C. Yet if emissions continue at current rates, within ten to fifteen years we will lose the chance to remain in a world at only 1.5°C. 

Jackson is also a senior fellow at the Precourt Institute for Energy and the Stanford Woods Institute for the Environment.

This story was adapted from the original report published by Exponential RoadmapThe roadmap was compiled by 55 authors from across academia, industry, policy and consultancy. The collaboration includes WWF, Future Earth, the Stockholm Resilience Centre, Stockholm University, PIK, Ericsson, M2020, KTH Royal Institute of Technology and Internet of Planet.  

Green belt near buildings


Researchers offer practical guide to planning and achieving green growth

Economic development plans often overlook a crucial detail – ecosystems that provide essential services to people. Stanford experts discuss a new sustainable development approach that balances the needs of people and nature.

Media Contacts

Danielle T. Tucker
School of Earth, Energy & Environmental Sciences, 650-497-9541

Rob Jackson
School of Earth, Energy & Environmental Sciences, 650-497-5841

Explore More