Cumulative Emissions

Introduction to Temperature Records and Carbon Budget

  • In 1850, a reasonably globally distributed temperature record from thermometers began.

  • Average temperature benchmark is set from 1850 to 1900 at zero degrees.

  • Industrial Revolution was beginning but not in full effect at this time.

  • To limit temperature increase to no more than two degrees Celsius above this benchmark, we can emit 400 gigatons of carbon before reaching a 50% chance of hitting that temperature threshold.

  • There are approximately 3,000 gigatons of carbon known to be in the ground, which can be extracted and burned, raising concerns about climate change.

Carbon Budget

  • The term "carbon budget" refers to the amount of carbon we can afford to emit while still attempting to avoid severe climate impacts.

  • The concept of "unburnable carbon" is introduced, which signifies carbon that, although physically burnable (e.g., coal), must remain unburned to meet climate goals.

Fossil Fuel Companies and Market Valuation

  • Fossil fuel companies remain highly valued despite the known presence of unburnable carbon.

  • The market has not significantly shifted away from fossil fuels over the last decade.

  • Two potential paths to consider if we are serious about limiting global warming to two degrees:

    1. We will not stop at two degrees.

    2. We plan to remove carbon from the atmosphere later.

Costs of Carbon Removal

  • It is noted that removing carbon from the atmosphere after burning it will be expensive due to low CO2 atmospheric concentration (approximately 0.04%).

  • The cost of carbon removal depends heavily on the amount of carbon emitted.

Temperature Projections Graph

  • Discussion of projected temperature anomalies from 1880 to the end of the century.

  • Various potential future emission scenarios include:

    • Constant emissions (yellow line)

    • Increased emissions by 2% annually (red line)

    • Reduced emissions strategies (green and blue lines)

Financial Projections for Carbon Removal

  • If emissions are reduced by 6% each year, the cost to remove CO2 from the atmosphere could be around $10 trillion.

  • Costs escalate dramatically with higher emission rates (e.g., up to $230 trillion).

  • Comparison made to the current US national debt, estimated around $38 trillion, showing that achieving emission reductions would still necessitate massive financial resources.

Climate Strategies

Three Main Strategies to Mitigate Climate Change:

  1. Mitigation:

    • Focus on reducing emissions now: electric vehicles, renewable energy, etc.

  2. Adaptation:

    • Modifying infrastructure to cope with climate impacts (e.g., building dikes, providing air conditioning).

  3. Geoengineering:

    • Deliberately altering climate systems to counteract climate change effects.

Geoengineering Approaches

Three Basic Geoengineering Strategies:

  1. Reducing Vulnerability of Climate System:

    • Making ice sheets more resilient to collapse.

  2. Removing CO2 from the atmosphere:

    • Techniques discussed to be explored.

  3. Solar Radiation Management (SRM):

    • Ideas for reflecting solar energy to cool Earth down.

Challenges in Geoengineering

  • Discussion on the need for careful planning and assessment of geoengineering proposals based on historical context:

    • Example: Johnson’s 1965 report on possible climate interventions.

    • Consideration of how doubling CO2 affects Earth’s radiation and potential for counteractive measures like increasing albedo.

Costs of Stabilizing Ice Sheets

Three Key Vulnerabilities:

  • Fast-flowing ice streams, unstable ice shelves, contact with warm ocean water.

  1. Slowing down ice streams:

    • Options include pumping out meltwater or cooling ice. Estimated cost could be $300 billion, likely needing multiple nuclear power plants.

  2. Stabilizing ice shelves:

    • Suggestions include infrastructure to physically hold ice shelves.

  3. Preventing warm water contact:

    • Idea to construct underwater barriers to maintain ice stability.

Carbon Removal Strategies

  1. Ocean Fertilization:

    • Adding iron to stimulate phytoplankton growth, which can sequester CO2.

  2. Bioenergy with Carbon Capture and Storage (BECCS):

    • Using plant biomass for energy while capturing emissions.

    • Issues around scale, cost, and land use questioned, especially the reliance on large land areas.

  3. Artificial Carbon Capture:

    • Technologies for direct air capture of CO2, though with limitations in efficiency compared to emissions sources.

Solar Radiation Management (SRM)

  • Discussion around potential benefits and risks, including:

  1. Immediate temperature control, potential for global cooling via aerosol injection.

  2. Risks like acid rain, that may exacerbate ocean acidification and require continuous operation of systems without interruption.

  3. Long-term implications of rerouting climate policy and human health concerns relayed.

  4. Potential for volcanic eruption analogs as a model for understanding SRM effects.

Concluding Thoughts on Climate Change

  • Key projections indicating sea level rise as a major climate change impact, emphasizing cumulative emissions' power in manipulating future climate outcomes.

  • Important contextual reflections on societal implications of rising sea levels on populated regions.

  • Critical reflections on human adaptability and policy implications as we consider options going forward in climate strategy.