geoengineering explained: the benefits and challenges of biochar

Biochar, a form of carbon dioxide sequestration (SDR), is a solid material obtained from the carbonization of biomass. This produces a highly porous charcoal. The biomass is then buried in order to lock the carbon into the soil which can improve soil functions and the CO2 typically produced by the natural degradation of biomass is reduced. This practice is over 2,000 years old and biochar can be found throughout the world as a result of forest fires and historic soil management practices.

BENEFITS

CHALLENGES

  • Slows actual climate change, rather than actively changing the climate itself
  • Slows the rate of ocean acidification
  • Enhances the soil and can be made from waste products, such as chicken manure
  • Sustainable biochar practices can produce oil and gas byproducts that can be used as fuel, providing clean, renewable energy
  • Measurable and verifiable carbon sequestration value
  • Competes with global fuel and food production
  • Will not prevent sea-level rises
  • Has questionable efficacy and is predicted to only have the ability to offset 10 percent of the warming caused by increases in CO2

see also:

Question: What is geoengineering?

Albedo Enhancement

Space Reflectors
Stratospheric Aerosols

Afforestation
Ambient Air Capture
Biochar
Bioenergy Capture and Sequestration
Ocean Fertilization
Enhanced Weathering
Ocean Alkalinity Enhancement

sources:
Initiative, I. B. (2014). What is Biochar? Retrieved from biochar-international.org: http://www.biochar-international.org/biochar
Ippolito, J. a. (2011, March 3-4). Biochar usage: pros and cons. Retrieved from http://eprints.nwisrl.ars.usda.gov/1522/
LePage, M. (2012, September 20). The pros and cons of geoengineering. 

question: what is geoengineering?

Geoengineering is deliberate, large-scale intervention in Earth’s natural systems to counteract climate change. The two most common forms are:

SOLAR RADIATION MANAGEMENT (SRM)

SRM techniques aim to reflect a small proportion of the Sun’s energy back into space, counteracting the temperature rise caused by increased levels of greenhouse gases in the atmosphere which absorb energy and raise temperatures. Methods include: albedo enhancement, space reflectors and stratospheric aerosols.

CARBON DIOXIDE REMOVAL (CDR)

These techniques aim to remove carbon dioxide from the atmosphere, directly countering the increased greenhouse effect and ocean acidification. These techniques would have to be implemented on a global scale to have a significant impact on carbon(4). Methods include: afforestation, biochar, bioenergy capture and sequestration, ambient air capture, ocean fertilization, enhanced weathering and ocean alkalinity enhancement.

A description of the different forms can be found in the following posts:

SRM:

Albedo Enhancement

Space Reflectors
Stratospheric Aerosols

CDR:

Ambient Air Capture
Afforestation

Biochar
Bioenergy Capture and Sequestration
Ocean Fertilization
Enhanced Weathering
Ocean Alkalinity Enhancement

geoengineering explained: the benefits and challenges of stratospheric aerosols

Stratospheric aerosols are minute particles suspended in the atmosphere designed for solar radiation management (SRM). When these particles are sufficiently large, their presence becomes noticeable as they scatter and absorb sunlight, which can reduce visibility (haze) and redden sunrises and sunsets. Aerosols interact both directly and indirectly with the Earth’s radiation budget and climate. As a direct effect, the aerosols scatter sunlight directly back into space. As an indirect effect, aerosols in the lower atmosphere can modify the size of cloud particles, changing how the clouds reflect and absorb sunlight, thereby affecting the earth’s energy budget. Aerosols can also act as sites for chemical reactions to take place. Stratospheric aerosols introduce small, reflective particles into the upper atmosphere to reflect some sunlight before it reaches the surface of the Earth. This is accomplished by releasing sulfur dioxide into the stratosphere.

BENEFITS

CHALLENGES

  • Very potent method and could off-set all the warming from the doubling of CO2
  • Affordable and relatively easy
  • Proven effective by large, natural volcanic eruptions
  • As with all sunshade schemes, overall rainfall is reduced
  • Regional weather climates will be dramatically affected which may cause dangerous outcomes, such as famine
  • Doesn’t cool poles to pre-industrial temperatures, so polar ice sheets will continue to melt
  • Will not prevent ocean acidification
  • Sky will become whiter
  • Without efforts to reduce overall CO2 production, the planet would warm rapidly if we stopped injecting SO2 into the stratosphere

see also:

Question: What is geoengineering?

Albedo Enhancement

Space Reflectors
Stratospheric Aerosols

Afforestation
Ambient Air Capture
Biochar
Bioenergy Capture and Sequestration
Ocean Fertilization
Enhanced Weathering
Ocean Alkalinity Enhancement

source:
LePage, M. (2012, September 20). The pros and cons of geoengineering. Retrieved from New Scientist: http://www.newscientist.com/gallery/geoengineering/

geoengineering explained: the benefits and challenges of space reflectors

Space reflectors, a form of solar radiation management (SRM), are sun shields positioned in space in order to reduce the amount of solar energy reaching the earth. Options include placing mirrors around the earth, placing millions of reflectors between the earth and the sun where the gravitational attraction between the two bodies is equal, launching a “cloud” of trillions of refracting discs or launching a sunshade of mesh aluminum threads.

BENEFITS

CHALLENGES

  • The theorized sun protection would be enough to stop global warming
  • Expensive [estimated at several trillion dollars]
  • Experimental technology with unforeseen consequences
  • Will take 25 years or longer to complete
  • Effects would be uneven with the tropics cooling and the polar regions warming

see also:

Question: What is geoengineering?

Albedo Enhancement

Space Reflectors
Stratospheric Aerosols

Afforestation
Ambient Air Capture
Biochar
Bioenergy Capture and Sequestration
Ocean Fertilization
Enhanced Weathering
Ocean Alkalinity Enhancement

sources:
Physics, I. I., RSC, & Engineering, T. R. (2009, July 15). Geoengineering: challenges and global impacts. Retrieved from http://www.rsc.org

 

geoengineering explained: the benefits and challenges of ocean fertilization

Ocean fertilization is an untested carbon dioxide sequestration (CDR) technique that involves dissolving nitrates or iron into the water which will encourage an increase in carbon uptake by phytoplankton. After the plankton blooms, it dies and then sinks to the ocean floor where the carbon will be stored as sedimentary rock.

BENEFITS

CHALLENGES

  • Relatively safe
  • Will slow the rate of ocean acidification
  • Does not directly change the actively changing climate, rather it slows future climate change
  • Will alter marine systems creating new potential problems
  • Will cause and/or accelerate ocean eutrophication

 

see also:

Question: What is geoengineering?

Albedo Enhancement

Space Reflectors
Stratospheric Aerosols

Afforestation
Ambient Air Capture
Biochar
Bioenergy Capture and Sequestration
Ocean Fertilization
Enhanced Weathering
Ocean Alkalinity Enhancement

sources:
The Editors of Encyclopædia Britannica. (2014). Ocean Fertilization. Retrieved from Britannica.com: http://www.britannica.com/EBchecked/topic/1563580/ocean-fertilization
LePage, M. (2012, September 20). The pros and cons of geoengineering. Retrieved from www.newscientist.com