Achieving Net-Zero: A Reason for Optimism in Climate Action
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At our current consumption rate, global oil reserves are projected to run out in under 50 years. This leads to a pressing question: what would be the rise in atmospheric CO? if we were to burn all the accessible oil? My estimation suggests an increase of approximately 58 ppm, highlighting how significantly oil reserves could elevate CO? levels.
This figure may be somewhat inflated since a fraction of oil is allocated for products like asphalt and plastics rather than solely for fuel.
To meet the target of net-zero carbon emissions by 2050, the U.S. must significantly reduce fossil fuel consumption.
In this discussion, I will outline the reasons for my optimism regarding this goal.
Oil Reserves and Their Impact
There is an immense amount of oil stored underground, estimated at around 1.65 trillion barrels (with one barrel equating to about 42 gallons). This stockpile has the potential to emit 230 gigatonnes of carbon (GtC).
Understanding Gigatonnes
A gigatonne (Gt) is synonymous with a petagram (Pg), which equals (10^{15}) grams. Another term you'll encounter is a billion tonnes, and all these units are interchangeable:
1 Gt = 1 Pg = 1 billion tonnes = (10^{15}) grams
To visualize this, a gigatonne of ice over Central Park would rise 341 meters (1,119 ft) into the sky, surpassing the height of the Chrysler Building.
Global Carbon Dynamics
If we were to extract and combust the entire 230 GtC of oil, where would the resulting carbon emissions end up? Approximately half would remain in the atmosphere, while the other half would be absorbed by vegetation through photosynthesis or absorbed by oceans.
This implies that around 115 GtC would linger in the atmosphere after combustion.
The next query is how this amount of carbon would affect atmospheric CO? levels. According to Professor David Archer in his book “The Global Carbon Cycle”:
> "A handy conversion factor is that 1 Gton C in our atmosphere changes the concentration of CO? by about 0.5 ppm."
This information allows us to convert carbon variations in the atmosphere into changes in CO? concentration. Thus, the 115 GtC that remains in the atmosphere from burning oil leads to an increase of 58 ppm.
This increase is strictly from oil and does not account for the substantial amounts of natural gas or coal that are also buried underground.
To mitigate the worsening effects of climate change by enhancing the greenhouse effect, it is essential to minimize the extraction of fossil fuels by transitioning to renewable energy sources.
Transitioning to Renewables
While addressing climate change is crucial, it’s not the only reason for shifting towards renewable energy. This transition also promotes energy independence for future generations and prevents potential energy crises. I believe that focusing solely on 1.5°C and climate impacts is hindering this transition. We must emphasize that the oil clock is ticking, with an alarm set to ring in about 50 years.
We must recognize the significant role that government policies will play in this transition. Regrettably, not everyone in Congress acknowledges the realities of climate change. However, registered voter support indicates that funding research into renewable energy is a common ground for both parties.
Nevertheless, contention arises regarding the requirement for utility companies to source a portion of their electricity from renewable sources.
Bridging the Communication Gap
I believe the root of this division lies in communication. It's challenging to change someone's perspective without first establishing rapport. There needs to be common ground. Campaigns like New Climate Voices aim to bridge the communication divide between scientists and conservatives by fostering a shared connection.
A legislative consensus is merely the initial obstacle; completely transitioning the nation to renewable energy will be a daunting task.
As electric vehicles become commonplace, our existing infrastructure will be tested as peak electricity demands are expected to rise by approximately 40-60%. The power grid is in urgent need of enhancements. Fortunately, the infrastructure bill allocates $65 billion for upgrades, though this amount falls short of what is necessary. The most significant challenge in moving to renewables will be transmission—transporting energy from generation sites (mainly in the Midwest) to consumption areas (the coasts).
Despite the hurdles, there are encouraging signs:
- Solar energy is now cheaper than coal.
- Renewables account for 20% of electricity generation in the U.S.
- They are the second most dominant energy source.
- Renewables represented most new generating capacity in 2021.
While these developments are promising, it’s crucial to acknowledge the challenges of fully transitioning the power grid to renewable energy, particularly concerning transmission. For a lighthearted take on this issue, refer to Last Week Tonight’s November 8th, 2021 episode.
The Impact of 2020
The events of 2020 had a measurable influence on global emissions. According to Nature News in January 2021, there was a notable decline in global CO? emissions. The article begins with the statement:
> "After rising steadily for decades, global carbon dioxide emissions fell by 6.4%, or 2.3 billion tonnes, in 2020, as the COVID-19 pandemic curtailed economic and social activities worldwide, according to new data on daily fossil fuel emissions."
This reduction occurred due to widespread lockdowns. A 6% drop in such a brief period is remarkable and is comparable to the annual decrease needed to limit warming to 1.5°C above pre-industrial levels.
What effect did this drop in emissions have on atmospheric CO? levels? This reduction prevented an additional rise of 0.15 ppm in concentration.
While this decline was temporary and its benefits fleeting, it reinforces my belief that achieving net-zero is possible.
Converting Emissions to ppm
The decrease in emissions was quantified as 2.3 GtCO?. To convert this to GtC, we can recall a few chemistry principles:
- 1 mole of carbon produces 1 mole of CO?.
- 1 mole of carbon weighs 12 grams.
- 1 mole of CO? weighs 44 grams.
From these facts, we deduce that 12 grams of carbon can create 44 grams of CO?. This gives us a straightforward conversion factor between CO? mass and its carbon content.
1 GtCO? * (12 gC / 44 gCO?) = 0.27 GtC
Using this to calculate the carbon contained in 2.3 GtCO?:
2.3 GtCO? * (0.27 GtC / 1 GtCO?) = 0.62 GtC
Thus, 0.62 GtC in emissions were avoided in 2020.
Now, applying our conversion factor between GtC and ppm:
0.62 GtC * (0.5 ppm / 1 GtC) = 0.15 ppm
The emission reduction in 2020 prevented atmospheric CO? concentration from rising by an additional 0.15 ppm.
Putting It All Together
Globally, carbon emissions hover around 10 GtC annually (or about 36 GtCO?), and this figure continues to grow. These emissions are responsible for the typical annual increase in atmospheric CO? of about 2.5 ppm.
Path to Net-Zero
To achieve net-zero by 2050, at what rate must we reduce carbon emissions each year? With 29 years remaining, we need to decrease our emissions from 10 GtC to 0 GtC, necessitating an average annual reduction of at least 0.34 GtC.
Following the 2020 dip, emissions are expected to rebound. However, if we maintain an average reduction of 0.34 GtC yearly, net-zero remains achievable. Once we reach net-zero, the progression of global warming will halt, allowing us to manage the extent of warming the planet experiences.
This straightforward calculation illustrates that if we can sustain even half the reduction seen in 2020 year after year, we stand a chance of achieving net-zero by 2050.
Considering the extensive impact of travel, shipping, and the economy during 2020, it is clear that we must begin the shift towards renewable energy. This transition will not be without difficulties, and sacrifices will be necessary. Nevertheless, the trends in renewable energy costs and usage are encouraging. If I can glean anything positive from 2020, it’s that this seemingly unattainable goal is, at the very least, feasible.
Despite current pledges, the world is likely to warm beyond 2°C by the century's end, a scenario that could have catastrophic consequences.
We should focus less on avoiding an unreachable temperature target and more on modernizing our power grid, making incremental cuts in carbon emissions, and preventing the complete combustion of oil to avoid a surge of an additional 50 ppm in atmospheric CO?.
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