Fifteen Eighty Four

Academic perspectives from Cambridge University Press


#EarthDay Can we still hope to meet a ‘Two Degree Scenario’

Frank Incropera

[Photo by Jean-Baptiste Gurliat/ Mairie de Paris]

Climate Change – Headwinds and Opportunities

Since 1995, member nations of the UN’s Conference of Parties (COP) have met annually to reach agreement on how to constrain greenhouse gas (GHG) emissions. But for 20 years, progress was impeded by sharp divisions, with poorer, developing nations arguing that the richer, developed nations must bear the burden of reducing emissions. That’s why the 2015 meeting in Paris (COP 21) was by all measures historic.

The stage was set in the run-up to Paris when the world’s two largest emitters agreed to substantive measures – China by restraining growth of its emissions and the US by achieving a 26% reduction by 2025. The measures provided an incentive for other nations, and by 2016 more than 190 had submitted Intended Nationally Determined Contributions (INDCs) for curbing their emissions.

While the INDCs, if fully implemented, would not put the world on a path to keep the Earth’s average surface temperature from rising more than 2°C above the pre-industrial value – a threshold with potentially unmanageable consequences − they represented a good beginning and, if augmented by additional contributions, could be the precursor to a two degree scenario (2DS).

Now, some 16 months after the Paris meeting, where do we stand?

Now, some 16 months after the Paris meeting, where do we stand?

The good news is that carbon emissions were roughly flat for the last three years, even as global GDP grew by more than 3% per year. But, can the trend be sustained? Or, more importantly, as a requirement for 2DS, can emissions begin a sharp decline before the end of the decade? The short answer is no!


Even if all nations abide by their INDCs, fossil fuels will remain a significant source of energy, and between 2015 and 2040 related emissions are projected to increase 0.5% per year (IEA, 2016a). Oil consumption will increase, with developing nations accounting for most of the growth, and although there will be little change in coal consumption, projections call for a 50% increase in natural gas.

after years of slowing the contribution of deforestation to carbon emissions, it is experiencing a revival.

Other factors will make it even more difficult to achieve 2DS. Because carbon capture and sequestration (CCS) for coal-fired power plants remains very expensive, it will fall far short of expectations for reducing emissions. The same may be said for carbon-free nuclear power. Also, leakage of methane – a potent greenhouse gas − during the production and use of natural gas will amplify its effect on warming. And, after years of slowing the contribution of deforestation to carbon emissions, it is experiencing a revival.

Then, beginning with the US, there’s the question of whether all nations will, in fact, honor their INDCs.

Cornerstones of the US INDC are the Clean Power Plan, which calls for a 32% percent reduction in power plant emissions by 2030, achieving a corporate average fuel economy standard of 54.5 miles per gallon for light duty vehicles by 2025, and a wide array of energy efficiency initiatives. Under a new administrator of the Environmental Protection Agency, one who dismisses human agents of climate change, these measures are in danger of being cancelled. The effect could well be one of weakening the resolve of other nations to realize their INDCs.

Hopeful Signs

Yet, there are hopeful signs, beginning with the rapid growth in renewable energy, enabled largely by improved performance and sharp drops in the cost of wind and solar power. Were this segment of the world’s INDCs implemented, the contribution of renewables to global power generation would increase from 23% to 37% by 2040. Another ray of hope is the projected growth in the number of electric vehicles (EVs), from 1 million to 150 million by 2040.

US, efforts to dilute its INDC will not go unopposed

Even in the US, efforts to dilute its INDC will not go unopposed. Actions by the federal government to eliminate constraints on emissions will be met by significant resistance from state and local governments, environmental groups, and a large segment of the business community.

Doubling Down

accelerating the growth of renewables and electric vehicles

Moving forward, emphasis must be placed on accelerating the growth of renewables and electric vehicles, as well as the pursuit of ever greater energy efficiency. Investing in 21st century electric grids – making them larger, smarter and tougher − is critical to the advancement of wind and solar energy. Expansion will smooth the cumulative output of dispersed and intermittent solar/wind farms and facilitate transmission from sparsely populated sun- or wind-rich regions of low demand to densely populated regions of high demand. A smarter grid will facilitate better control over supply and demand, while a tougher grid will increase resilience to cyber attack and extreme weather.

To achieve the full potential of EVs and intermittent sources of renewable energy, emphasis must also be placed on increasing the performance and reducing the cost of battery (storage) technologies. And, with more than 1/2 of the world’s population living in urban environments, the frontline of energy efficiency must be in smart city initiatives that reduce transportation and building energy consumption while maximizing distributed sources of energy, including microgrids.

Large investments must be made in these and other sectors. If CCS is to achieve meaningful scales of reducing emissions from coal-fired power plants, gas separation technologies must be advanced to reduce related costs. The cost of producing biofuels from nonedible biomass such as recycled paper and wood products or agricultural residues must also be reduced. The contribution of carbon-free nuclear power must be enhanced, particularly through the development of small modular reactors.

none of these objectives can be met without stimulative monetary and fiscal policy

But none of these objectives can be met without stimulative monetary and fiscal policy. Incentives such as tax-free green-bonds, production and investment tax credits, rebates for building energy efficiency and EVs, and a carbon tax go a long way toward stimulating investments by the private sector.

Although achieving 2DS is unlikely, technology and policy are vital instruments for reducing the gap. But in a circa-2050 world inhabited by more than 9 billion people, each with expectations for Western living standards, more will be needed.

Addressing Cultural Norms

Wasteful habits of consumption must be addressed

At some point, the current economic model of growth based on consumption will no longer be scalable, making globalization of Western levels of energy consumption more than problematic. Conservation must become a core social value. Wasteful habits of consumption must be addressed in developed nations, while people’s expectations are moderated in developing nations.

For the first Earth Day in 1970, Walt Kelly, creator of a popular cartoon strip, released a poster showing the dismay of its central character Pogo over natural surroundings overwhelmed by human detritus. The now famous caption read,

“We Have Met the Enemy and He Is Us.”

How we use energy to meet our wants and needs matters − a great deal.


Read Frank Incropera’s earlier article:  Climate Change and Paris 2015 − Pessimism or Cautious Optimism? Where he explores the role Conference of Parties at the time of the Paris meeting in 2015.


More articles on the Paris Climate Summit:


Further Reading:

IEA (2016a). World Energy Outlook 2016. International Energy Administration (www.iea.org/newsroom/news/2016/november/world-energy-outlook-2016.html).

Kelly, W. (1970). We Have Met the Enemy and He Is Us (http://www.thisdayinquotes.com/2011/04/we-have-met-enemy-and-he-is-us.html).

About The Author

Frank Incropera

Frank Incropera is author of Climate Change: A Wicked Problem (2015). He is Clifford and Evelyn Brosey Professor of Mechanical Engineering at the University of Notre Dame, where he...

View profile >

Latest Comments

Have your say!