“Bending the Curve” of Greenhouse Gas Emissions and Climate Change

Exponential Emissions

At current greenhouse gas emission levels, the earth’s temperature is projected to rise by 2.5 to 7.8 degrees Celsius by the end of this century.

If that doesn’t seem like a lot, consider the recent climate-related changes in our environment: frequent and severe weather events like storms, drought and rising sea levels. All of this is from an increase of .9 degrees Celsius most likely caused by human activities, including releasing CO2 and other greenhouse gases into the atmosphere.

CO2 and other greenhouse gases surround the planet like a blanket that traps infrared energy normally reflected back into space. At the current rate of CO2 emissions, the temperature is set to rise by two degrees in less than 40 years, causing not just climate change but major climate disruption.

Bending the Curve

Right now, the graph to illustrate human-caused global warming looks like an exponentially increasing upward curve. Under the University of California’s Carbon Neutrality Initiative, all 10 UC campuses intend to bring down their climate impact by achieving zero net greenhouse gas emissions by 2025. Over 50 UC researchers and scholars participated in a climate solutions team that collaborated on the report, “Bending the Curve.” The title refers to flattening the upward temperature trajectory on a climate graph and ultimately bringing it down. 

Upward graph showing projected global warming possible with different levels of mitigation.

Graph from “Bending the Curve Executive Summary” published by University of California.

There is a consensus that reducing CO2 emissions 80% by 2050 and then maintaining carbon neutrality after 2050 would begin to bend the curve and reduce overall warming by as much as 1.5 degrees Celsius by 2100. Even more rapid reductions in temperature are possible by reducing four short-lived climate pollutants (SLCPs): methane (CH4), black carbon, hydrofluorocarbons (HFCs) and tropospheric ozone. If we implemented all the technologies we have for reducing SLCPs by 2030, projected warming could be reduced by up to .6 degrees Celsius within two to four decades, keeping warming well below 2 degrees Celsius at the 2050 mark.

Ten Solutions

Institutions can scale the 10 solutions outlined in the “Bending the Curve” report to keep global warming at a manageable level and bend the curve. Seven of the solutions have been, or currently are, implemented and several of them have been field tested on UC campuses. If implemented, these solutions would keep global warming around two degrees Celsius, the critical tipping point, through 2100 and provide more time for the world to adapt the technology and policies to become carbon neutral.

1. Bend the warming curve immediately by reducing short-lived climate pollutants (SLCPs). This can be achieved by replacing current fossil-fueled energy systems with carbon neutral technologies. Solution #7 and #9 contain technological solutions to reducing SLCPs.

2. Foster a global culture of climate action through public communication and education at local and global scales. Although a broad and expansive task, combining tech and policy solutions with innovative approaches can change social attitudes and behavior towards climate change.

A hand holding an iPhone taking a photo of leaves.Climate Champion Claire Napawan at UC Davis is using #OurChangingClimate to provide an online space where people can share their everyday interactions with climate change and learn about the effects of climate change.


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3. Deepen global culture of climate collaboration by designing venues where people can converge around concrete problems with researchers and scholars from all academic disciplines, with the goal of beginning collaborative action to mitigate climate disruption.

Sea creature under waterProfessor Gretchen Hofmann at UC Santa Barbara is one of the many Climate Action Champions expanding beyond her field to reach non-science audiences. She is forming a team of outreach specialists for climate change issues endangering the California coast and putting together an art show that features organisms she researches.

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4. Scale up subnational models of governance and collaboration around the world to embolden and energize national and international action. With California as a model of a living laboratory that tests different approaches and researches sustainable solutions, other states and cities could also pursue renewable technologies and market-based solutions.

Hydrogen bus unveiled at UCIUC Irvine demonstrates a sustainable and affordable approach to transportation with their fleet of electric and hydrogen fuel cell buses that don’t emit any carbon dioxide and provide transportation for the 1,500 acre campus.

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5. Adopt market-based tools to create incentives for businesses and individuals to reduce CO2 emissions. This can include cap and trade (a government mandated cap, or limit, on emissions that promotes trade in carbon allowances and rewards low emissions) and adopting technology that keeps inventory of emissions to monitor and enforce these approaches.

6. Narrowly target direct regulatory measures (rebates and efficiency and renewable energy portfolio standards) at high emissions sectors not covered by market-based policies. Create more incentives that reward improvements in bringing down emissions, eliminate subsidies that encourage emission-intensive activities and expand subsidies that encourage innovation in low emission technologies.

7. Promote immediate widespread use of mature technologies, such as photovoltaics, wind turbines, battery and hydrogen fuel cell electric light-duty vehicles, and more efficient end-use devices especially in lighting, air conditioning, appliances and industrial processes. If these products are the target of market-based or direct regulatory solutions like those discussed in solutions #5 and #6, they can potentially achieve 30-40% reduction in CO2 emissions by 2030.

UC Davis is home to California Wind Energy Collaborative which seeks to develop cost effective and reliable wind power in California by promoting research, coordinating with other parties, resources and interests and providing education about wind power.

Wind turbines on green hillside

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8. Aggressively support and promote innovations to accelerate the complete electrification of energy and transportation systems and improve building efficiency. Support the development of lower-cost energy storage for transportation and energy distribution grids. Support the development of new energy storage and usage technologies, for tools and resources like batteries, compressed air, hydrogen and thermal storage, heat pumps, efficient lighting, fuel cells, smart buildings, and systems integrations. These technologies are an important part of reaching the target of 80% reduction of CO2 by 2050.

A man holds a surfboard on the beachClimate Champion Robert (Skip) Pomeroy at UC San Diego creates biofuel from algae, as an alternative to petroleum, and he has built an algae-fueled motorcycle and an algae-based surfboard.

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9. Immediately make maximum use of available, existing technologies and regulations to reduce methane emissions by 50% and black carbon emissions by 90%. Phase out HFCs by 2030 by amending Montreal Protocol, the 1989 international treaty that addresses substances that deplete the ozone layer. In October 2016, the United Nations Environment Programme added an amendment to phase out HFCs, but it has not yet entered enforcement. In addition to the climate and health benefits described under solution #1, this solution will provide access to clean cooking for the poorest three billion people who collect solid biomass fuels to burn for cooking.

10. Regenerate damaged natural ecosystems and restore soil’s organic carbon to improve natural sinks that absorb CO2. Implement food waste reduction programs and energy recovery systems to maximize utilization of food produced and recover energy from food not consumed. Global deployment of these measures could reduce the current 50 billion tons of CO2 and greenhouse gas emissions emitted annually by 20%.

Sheep stand on a green hillside with treesClimate Champion Whendee Silver’s “garbage to grasslands” project takes organic waste from her campus, UC Berkeley, composts it and applies it to surrounding grasslands, which serves the dual purpose of managing waste and increasing carbon storage in soil.

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As a leader in sustainability technology, policies and implementation, the University of California has taken many steps to mitigate global warming, but it will take even greater measures to change the projected global consequences. These 10 solutions, while pragmatic, will not be easy to achieve and will require innovation and collaboration to succeed at bending the global warming curve.

Read Bending the Curve Report

By Nicole Block, Climate Communications Student Writer