The Oil Reserves

There exists an estimated 1.65 trillion barrels of oil underground, capable of releasing around 230 gigatonnes of carbon (GtC). For context, a gigatonne (Gt) is equivalent to a petagram (Pg), which equals 10¹⁵ grams. To visualize, a gigatonne of ice covering Central Park would rise to 341 meters (1,119 ft), surpassing the height of the Chrysler Building.

The Global Carbon Cycle

If we were to extract and combust all 230 GtC of oil, where would the emissions go? About half would linger in the atmosphere, while the remainder would be absorbed by plants through photosynthesis or dissolve in oceans. Therefore, burning all that oil would leave roughly 115 GtC in the atmosphere.

According to Professor David Archer in "The Global Carbon Cycle," one gigatonne of carbon in the atmosphere increases CO₂ concentration by approximately 0.5 ppm. Thus, the 115 GtC remaining in the atmosphere from oil combustion would elevate CO₂ levels by 58 ppm. This figure pertains only to oil, without factoring in natural gas or the vast coal reserves underground.

To mitigate the effects of climate change and prevent intensifying the greenhouse effect, we must prioritize keeping fossil fuels underground and shift towards renewable energy sources.

The Transition to Renewables

Addressing climate change is essential, but it's not the sole reason for transitioning to renewable energy. This shift would promote energy independence and avert potential future energy crises. Emphasizing 1.5°C as a primary goal may hinder progress; we must recognize the urgency—our oil reserves are finite, and the alarm will sound in about 50 years.

Government policies will be critical in this transition. Unfortunately, not all lawmakers acknowledge the climate change realities. However, there is bipartisan support among voters for funding renewable energy research.

Where disagreements arise is in mandating utilities to source a portion of their electricity from renewable resources. This division may stem from communication barriers; establishing common ground is essential. Initiatives like New Climate Voices aim to bridge the gap between scientists and conservatives by fostering shared understanding.

A congressional consensus is merely the initial step in the arduous journey towards a renewable energy future. The existing infrastructure will face significant strain as electric vehicle use surges, potentially increasing peak electricity demand by 40-60%. Thankfully, the infrastructure bill allocates $65 billion for upgrades, though more funding is essential. The primary challenge remains in energy transmission—transporting energy from generation sites (like the Midwest) to where it is needed (the coasts).

Despite the challenges, there are reasons for optimism:

• Solar energy has become more affordable than coal.
• 20% of U.S. electricity is generated from renewables.
• Renewables are the second most prevalent energy source.
• Most new generation capacity in 2021 came from renewable sources.

While these developments are promising, we must not overlook the substantial challenges in completely transitioning the power grid to renewable energy, particularly regarding transmission. For a humorous perspective on this issue, refer to the November 8th, 2021 episode of Last Week Tonight.

The Impact of 2020

The events of 2020 significantly influenced global emissions. According to Nature News, global CO₂ emissions dropped by 6.4% (2.3 billion tonnes) due to the COVID-19 pandemic, which curtailed economic and social activities worldwide. This decline mirrors the annual reductions required to limit warming to 1.5°C above pre-industrial levels.

But what does this drop in emissions mean for atmospheric CO₂ concentration? It turns out that this reduction prevented an additional 0.15 ppm increase in CO₂ levels.

Though this decline was temporary, it provides hope that reaching net-zero emissions is feasible.

Converting Emissions to ppm

The 2020 emission drop amounted to 2.3 GtCO₂. To convert this to GtC, we can apply some chemistry principles:

• 1 mole of carbon produces 1 mole of CO₂.
• 1 mole of carbon weighs about 12 grams.
• 1 mole of CO₂ weighs about 44 grams.

Using this information, we find that 12 grams of carbon generates 44 grams of CO₂, enabling us to create a conversion factor between the mass of CO₂ and its carbon content.

Calculating for the 2.3 GtCO₂ emission reduction:

2.3 GtCO₂ * (12 gC / 44 gCO₂) = 0.62 GtC

This suggests that 0.62 GtC in emissions was avoided in 2020.

Utilizing our conversion factor between GtC and ppm:

0.62 GtC * (0.5 ppm / 1 GtC) = 0.15 ppm.

Thus, the reduction in emissions averted an additional increase of 0.15 ppm in atmospheric CO₂.

Putting It All Together

Globally, carbon emissions hover around 10 GtC annually (approximately 36 GtCO₂), and this figure continues to rise. These emissions are responsible for an average annual increase of about 2.5 ppm in atmospheric CO₂.

To achieve net-zero by 2050, we need to determine the necessary annual reduction rate. With 29 years remaining, we must decrease our emissions from 10 GtC to 0 GtC. This translates to an annual reduction of at least 0.34 GtC.

Although emissions are anticipated to rebound after the 2020 drop, consistently reducing emissions by an average of 0.34 GtC annually makes net-zero a plausible target. Achieving net-zero will halt global warming, allowing us to regulate the temperature rise.

This simplified calculation illustrates that maintaining even half of the emission decrease seen in 2020 could lead us to net-zero by 2050.

The challenges ahead are significant, and sacrifices will be necessary as we transition to renewable energy. However, the trajectory of renewable energy costs and usage is promising. If there's one lesson I take from 2020, it's that this seemingly unattainable goal is not out of reach.

The world is likely to warm by over 2°C by the century's end if current pledges remain unchanged—a scenario that could have dire consequences.

Instead of fixating on an arguably unreachable temperature target, we should prioritize modernizing our power grid, making reasonable cuts in carbon emissions, and minimizing fossil fuel combustion to prevent a surge of 50 ppm in atmospheric CO₂.

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