We Can Still Save the Climate
It’s natural to feel discouraged about global warming, because the Earth is continuing to heat up which is beginning to have serious effects, and yet current actions are insufficient to stop it. It’s not hopeless! There are two main reasons to think that the renewable energy transition is possible. Many countries, cities, businesses, and individuals have already transitioned in large part to renewables, reflecting a worldwide shift in perspective. Also, multiple lines of research with varying considerations have found viable pathways using today’s constantly improving technology.
Some selected references follow at the end.
Since technology has contributed to carbon pollution there is understandable distrust of technological solutions. But what we have now is dirty, inefficient technology which we depend upon every day for energy for almost everything we do, and which can be replaced by clean technology.
Technology is not the only answer. Planting trees and other natural solutions are very important, as they have the capacity to absorb years of our carbon emissions over the next decades, and compensate for any remaining fossil fuels. If only they could absorb most of it!
Energy conservation yields immediate reductions in carbon emissions, speeding up the transition to renewables. This includes such things as improved building insulation, driving EVs and/or driving less, installing heat pumps, buying only what we need, traveling less, and low-carbon food choices. However, most changes require governmental action and business initiatives, and collectively we can and must have an impact on both government and businesses.
But we have record temperatures and tipping points! How do we know that it’s not too late? We don’t know with absolute certainty, but among the thousands of scientists weighing in on this matter there is almost universal agreement that with changes in policy and behavior there is still time. Tipping points aren’t all or nothing, they are gradual processes. Some tipping points have already begun and may be impossible to stop completely, such as ice melt resulting in a gradual ocean level rise over decades and centuries, but we can still limit the destruction. Arctic warming is faster than had been predicted, so we are in some danger there. But runaway warming is not a given yet. Given the slight chance that we won’t stop the warming before it runs away on us, our obligation to deal with it doesn’t decrease, it only increases!
Most of all we need to reduce carbon emissions which are primarily from burning fossil fuels for energy. It’s important to note the often-ignored distinction between electricity and energy as a whole. Electricity is only a fraction of worldwide energy use, yet it’s vitally important as it forms the predominant basis for transitioning off of fossil fuels as we change over to electric vehicles, electric heat pumps, and electric industrial power.
In the US for instance, electricity (which is around 60% from fossil fuels) accounts for around one quarter of our carbon emissions. The other three quarters can be split almost evenly into 1) transportation, 2) industrial processes such as metals, concrete, and chemicals, and 3) the combination of commercial, residential, and agriculture (EPA, 2021). Transitioning to renewable electricity is only a part of the solution; all the other energy use needs to be electrified. This might seem discouraging, but energy conservation will help, and as I will cover a bit later, the far better efficiency of electric power over burning of fossil fuels also reduces the additional electrical demand.
Of the possible sources of renewable electricity, wind and solar are the best although they depend on the weather and daylight. Wind and solar can be deployed quickly at low cost and are among the lowest carbon. For more consistent power there are hydroelectric power and geothermal energy, and tidal and wave energy. Other options in use are nuclear and bioenergy, both controversial. We all know the drawbacks of nuclear power, and yet it continues to provide stable low-carbon power. Bioenergy can consume existing waste gasses or material, or create and store synthetic fuels produced using renewable electricity. Or it can be a harmful process such as burning wood pellets from clearcutting forests.
There are many good approaches for smoothing out the intermittency of wind and solar. Batteries work well over periods of hours and can respond in seconds to increased demand, faster than power plants. Other options for storing electrical energy are pumped hydroelectric storage, flow batteries, compressed air storage, hydrogen storage, and thermal storage. Grid interconnection over large distances evens out variations due to local weather very well. In some cases power consumption can be deferred to times when there is excess, such as for car charging.
Seasonal fluctuations may be more difficult, since short-term storage is not enough, but other kinds of power generation such as hydroelectric or bioenergy will help, as will grid interconnection. In my personal opinion, and as a last resort, some existing natural gas plants could be ready to fire up only when required, to prevent loss of power in unusual situations.
Here are a few examples of countries which have made outstanding progress toward renewable electricity, some relying heavily on wind and solar. The solutions chosen make sense for each situation. Many also have plans to electrify the rest of their energy in a few decades.
Scotland has 97% renewable electricity, up from 24% in 2010, and wind is a whopping 78% of that.
Denmark’s electricity is at 54% wind and 6% solar, with another 18% from bioenergy.
Costa Rica has been 98% renewable for eight years, mostly hydroelectric and geothermal, with 12% wind. Iceland is similar, as is New Zealand.
Uruguay has rapidly ramped up renewables from only 1% in 2013 up to 67% in 2021 (wind/hydro/solar), with a significant 31% from wind alone.
Australia has a solar portion of 13%, along with 11% from wind.
Unfortunately, the US is lagging behind with only at 10% wind and 4% solar at this time, so we must catch up. However, California leads the way with 27% solar and Texas with 28% wind.
China is often blamed for its leading carbon emissions, but they are actually doing fairly well overall. Their per-capita emissions are much lower than the US, they are leaders in manufacturing and installing solar, and so far they haven’t generated as much carbon pollution as the US has historically, and historical emissions are what have led to the current level of warming.
An encouraging recent development is the rapid adoption of electric vehicles, at 14% of new cars worldwide now, a trend which is accelerating and will continue to do so. Other trends can follow, such as the installation of heat pumps.
So we have some excellent examples of progress, but it would be good to make detailed predictions for the future worldwide. While we can’t predict the future with certainty, scientists have created very sophisticated models of our socioeconomic and technological systems called Integrated Assessment Models (IAM). They integrate different kinds of energy technologies, how we use energy and land, social trends, economic theories, historical data, in addition to a climate model. Human choices determine the inputs to these models, and these are called Shared Socioeconomic Pathways (SSP). The SSP is a kind of possible storyline incorporating different attitudes toward the environment, policies, economic conditions, population, education, urbanization, technological choices, development and costs, and energy demand. Together an IAM and SSP form a possible outcome. Some 3000 of these are used in the IPCC reports, and they have found pathways to 1.5 or 2 degrees C, although it’s unlikely today that we can limit warming to 1.5. These IAM/SSPs are grouped into several categories from business-as-usual to moderate action to wholehearted action.
There are various model assumptions which may or may not be valid: a growth economy, choices for or against nuclear power, bioenergy, and carbon capture and storage (CCS). Because of general sentiment that we won’t make changes as rapidly as we need, CCS plays a significant role after 2050 in most (but not all) IAM/SSP models, where they hope to be able to draw out carbon dioxide from the atmosphere and reverse the overheating to some extent. Once the carbon is captured it needs to be either stored or utilized (CCU). Carbon capture is very controversial for a number of reasons, among them that it might not actually reduce emissions, is costly, and may not be able to scale up.
Given that CCS may not pan out, we need to make the renewable transition much more rapidly than what current sentiments and market forces can deliver. Many researchers have modeled and proven out the viability of solutions without CCS. Two pioneers are Christian Breyer, who has a very detailed report on 100% renewable energy research (in the links), and Mark Jacobson, who has focused on wind, hydroelectric, solar, and geothermal energy. Breyer and others have added focus on bioenergy and synthetic fuels produced by renewable energy, which help deal with seasonal changes.
An early (2009) but good article coauthored by Jacobson appeared in Scientific American, “A path to sustainable energy by 2030”, which has great charts for power sources and power demands. It also covers some material shortages and intermittency. Renewables are cost-effective and solar has become drastically less expensive since then.
One study focuses on the challenging case of Kazakhstan, a country with high per-capita carbon emissions and cold winters, with high industrial energy demand, “Full energy sector transition towards 100% renewable energy supply: Integrating power, heat, transport and industry sectors including desalination”. Solutions are found over all energy sectors in spite of the challenges.
The huge 2019 report “Global Energy System Based on 100% Renewable Energy” is a very good example of a study modeling the possibility of transitioning energy as a whole to renewables driven mainly by wind and solar, modeling the world by nine major regions and 145 sub-regions. There are many charts and interesting world maps.
They write:
“A global transition to 100% renewable energy across all sectors — power, heat, transport and desalination before 2050 is feasible. Existing renewable energy potential and technologies, including storage, is capable of generating a secure energy supply at every hour throughout the year. The sustainable energy system is more efficient and cost effective than the existing system, which is based primarily on fossil fuels and nuclear. A global renewable transition is the only sustainable option for the energy sector, and is compatible with the internationally adopted Paris Agreement. The energy transition is not a question of technical feasibility or economic viability, but one of political will.”
Naturally the transition to renewable electricity brings with it many concerns. One is that we will need too much electricity as we absorb all the other energy usage. Energy conservation efforts will reduce the demand for electricity. Also, burning fossil fuels generally wastes more energy than it delivers, so there is far less electrical energy required than the energy contained in gas and oil that it replaces.
Transportation based on fossil fuels is extremely inefficient, with around 75% of the energy just converted into waste heat. This means that the energy from electricity needed to support electrified transportation needs is roughly 25% of what we’re using from fuel. Most other uses of energy from combustion are relatively inefficient, producing mostly waste heat, although for some applications it’s reasonable: it can be as much as 64% for combined-cycle gas turbine generators, and for gas furnaces from 56% to over 98%. For heating though, electric heat pumps are typically twice as efficient as direct heating (200% or more), since they don’t create heat but move it one way or another using evaporation and condensation.
Raw material shortages are another concern. It’s true that the supply chain for various metals is insufficient, however there are ways to deal with this, including ramping up mining, better recycling, and choosing alternate materials.
Then there is the cost of the transition, and we do need far more investment in renewable energy, trillions of dollars, but it’s both necessary and economically sensible as renewables are dropping below the cost of fossil fuels. And global warming is very expensive, ultimately more than we need to invest to prevent it.
As far as we know, it’s not too late to stop runaway warming, so we need ramped-up worldwide action, focused on renewable technology and energy conservation. With many options for renewable energy we can advocate for any of them which are honestly and clearly low carbon, which are wind, solar, hydroelectric, and geothermal. We may also be inclined to include nuclear, even with its well-known drawbacks, because it continues to help provide steady power with moderate associated carbon emissions. Bioenergy has promise if it uses existing wastes.
In the near term there is no reason not to favor wind and solar, as they are the best solutions all-around. As time progresses and they become predominant there will have to be more storage and other solutions to cope with intermittency.
Some countries are leaders in the renewable transition, demonstrating that it can be done. They use different technologies to match their various situations. Modeling also shows that there are many possible pathways which can be tailored for each situation.
We must act together, the sooner the better. There are only personal, corporate, and political barriers holding us back. What holds us back individually and collectively is a fascinating, mysterious, and troubling subject that deserves more attention.
References
Trees and renewable agriculture are very important for speeding reductions and for net negative emissions in the future. Ramped-up natural solutions would reduce the need for controversial bioenergy with carbon capture and storage (BECCS) which is controversial, especially when it requires large areas of cropland and even clear-cutting. “The PNAS paper’s best estimate of the total cost-effective potential for natural solutions is 225 GtCO2.” Compare this with worldwide carbon emissions of 37 GtCO2 in 2022, so natural solutions have an absorption capacity of 6 years of emissions total. “Analysis: How ‘natural climate solutions’ can reduce the need for BECCS” https://www.carbonbrief.org/analysis-how-natural-climate-solutions-can-reduce-the-need-for-beccs/ (from 2018)
Tipping points overview — note that most tipping points are still on the horizon, but they must be taken seriously. https://www.carbonbrief.org/qa-climate-tipping-points-have-put-earth-on-disastrous-trajectory-says-new-report/
Permafrost methane is widely understood to be a gradual release. https://www.carbonbrief.org/guest-post-the-irreversible-emissions-of-a-permafrost-tipping-point/
However, the Arctic is warming faster than predicted https://www.carbonbrief.org/the-arctic-has-warmed-nearly-four-times-faster-than-the-global-average/
2021 US by category, with 25% from electricity https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions
US 2023 electricity is solar/wind = 3.9%/10.2%, fossil fuels 60% https://www.eia.gov/tools/faqs/faq.php?id=427&t=3
Carbon footprints of energy sources https://ecochain.com/blog/the-co%e2%82%82-footprint-of-different-energy-sources/
A very detailed breakdown of global carbon emissions into categories, 2016 https://ourworldindata.org/ghg-emissions-by-sector
Various countries’ renewable electricity https://www.visualcapitalist.com/mapped-solar-and-wind-power-by-country/
Scotland’s electricity is almost entirely renewable, and they have a legally binding target of net-zero emissions by 2045. Solar/wind in 2023 are 568/(9593+2983) out of 15,358 MW, or 3.7%/81.9% https://www.scottishrenewables.com/our-industry/statistics
https://www.bbc.com/news/uk-scotland-56530424
Other countries:
https://www.iea.org/countries/denmark
https://www.iea.org/countries/costa-rica
https://www.iea.org/countries/uruguay
https://www.iea.org/countries/australia
California is leading in solar (27%)
Texas is leading in wind (28%) https://comptroller.texas.gov/economy/economic-data/energy/2023/wind-snap.php#:~:text=Texas%20Wind%20Energy%20Produced,the%20most%20of%20any%20state.
EV sales by country, total 14% of new cars https://www.virta.global/en/global-electric-vehicle-market
IAM and SSP overview https://www.carbonbrief.org/qa-how-integrated-assessment-models-are-used-to-study-climate-change/
The IPCC AR6 Report, Ch.3. See p.310–312 charts: LD = low-demand scenario depends on rapid transition to renewables instead of BECCS https://www.ipcc.ch/report/ar6/wg3/downloads/report/IPCC_AR6_WGIII_Chapter03.pdf
Is Capturing and Storing CO2 Emissions from Fossil Fuels a Viable Climate Solution? https://www.ucsusa.org/resources/capturing-and-storing-co2-emissions-viable-climate-solution
Expert assessment concludes negative emissions scenarios may not deliver https://iopscience.iop.org/article/10.1088/1748-9326/11/9/095003
An excellent overview of a path to 100% renewables, 2009, M. Z. Jacobson and M. A. Delucchi, ‘‘A path to sustainable energy by 2030,’’ Sci. Amer., vol. 301, no. 5, pp. 58–65, Nov. 2009, doi:10.1038/scientificamerican1109–58. https://www.researchgate.net/publication/38052436_A_Path_to_Sustainable_Energy_by_2030
“Full energy sector transition towards 100% renewable energy supply: Integrating power, heat, transport and industry sectors including desalination.” This is for Kazakhstan as an example with its severe weather and high energy demand for heating. https://www.sciencedirect.com/science/article/pii/S0306261920316639
This huge report is full of charts and a worldwide map detailing the results of a study on transitions of power, heat, transport, and desalination, avoiding nuclear and carbon capture. Electricity demand projected to be only slightly higher than current levels. This includes all energy sectors and allows for bioenergy but not nuclear. “Global energy system based on 100% renewable energy–power, heat, transport and desalination sectors” https://ccsi.columbia.edu/sites/default/files/content/docs/EWG_LUT_100RE_All_Sectors_Global_Report_2019.pdf
Around 20% efficiency for gasoline, 90% for electric vehicles https://www.motortrend.com/news/evs-more-efficient-than-internal-combustion-engines/
Large combined-cycle gas power plants are up to 64% efficient https://www.asme.org/topics-resources/content/blog-gas-power-plants-are-efficiency-giants
Gas furnaces are from 56% to nearly 100% efficient https://www.energy.gov/energysaver/furnaces-and-boilers
An excellent detailed history with many references, and responses to criticisms on cost, short-term variability, stability, and material shortages. “On the History and Future of 100% Renewable Energy Systems Research” https://ieeexplore.ieee.org/abstract/document/9837910
