In SummaryProposed strategies of GeoengineeringGEOL 108Lg 1st Edition Lecture 23Outline of Last Lecture- Renewable and Alternative EnergyOutline of Current Lecture-Adaptation and mitigation -Geoengineering: Types and SpecsCurrent LectureWhat to do about climate change?●Adaptation“initiatives and measures to reduce the vulnerability of natural and human systems against actual or expected climate change effects”Pros: we’ve always done it. Cons: glaciers, coral reefs, polar bears and poor people can’t adapt●Mitigation“measures or actions to decrease the intensity of radiative forcing in order to reduce the magnitude of climate change”Pros: Only sensible solution in the long run.Cons: more costly and will take a long time to implement and bear fruitClimate mitigation is any action taken to permanently eliminate or reduce the long-term risk andhazards of climate change to human life, property.The International Panel on Climate Change (IPCC) defines mitigation as: “An anthropogenic intervention to reduce the sources or enhance the sinks of greenhouse gases.” Climate Mitigation and AdaptationClimate adaptation refers to the ability of a system to adjust to climate change (including climatevariability and extremes) to moderate potential damage, to take advantage of opportunities, or to cope with the consequences.The IPCC defines adaptation as the, “adjustment in natural or human systems to a new or changing environment. Adaptation to climate change refers to adjustment in natural or human systems in response to actual or expected climatic stimuli or their effects, which moderates harm or exploits beneficial opportunities. Various types of adaptation can be distinguished, including anticipatory and reactive adaptation, private and public adaptation, and autonomous and planned adaptation.”In general the more mitigation there is, the less will be the impacts to which we will have to adjust, and the less the risks for which we will have to try and prepare. Conversely, the greater the degree of preparatory adaptation, the less may be the impacts associated with any given degree of climate change.Planned adaptations to climate change.Geoengineering-What if we cannot reduce greenhouse gas emissions in time (i.e. this century)?Geoengineering●Carbon dioxide removal methods●Solar radiation managementThe concept of geoengineering (or climate engineering, climate remediation, and climate intervention]) refers to "the deliberate large-scale intervention in the Earth’s climate system, in order to moderate global warming". The above two categories are what geoengineering techniques seek to cater too.(Keep in mind the global carbon cycle when reading these notes, refer to earlier lectures fordiagrams and description)Carbon dioxide removal methods: Land OceanBiological Afforestation and land useBiomass/fuels with carbon sequestration (the capture of Co2)Iron fertilizationPhosphorus/nitrogenFertilizationEnhanced upwellingPhysical Atmospheric Co2 scrubbers (‘air capture’)Changing overturning circulationChemical (‘enhanced weathering’ techniquesCarbonation of Silicates Alkalinity enhancement (grinding, dispersing and dissolving limestone, silicates, or calcium hydroxide)Land use and afforestationEffectiveness Limited potential for carbon removalLowAffordability Cheap to deploy Very highTimeliness Ready for immediate deploymentMediumSafety Few undesirable side effects for potential land use conflictsand biodiversity implicationsHighSolar Radiation MangementSpace Based Methods (Yes, space!)GeoengineeringIn Summary Geoengineering has been proposed as a potential third option for tackling global warming, alongside mitigation and adaptation. Scientists do not typically suggest geoengineering as an alternative to emissions control, but rather an accompanying strategy. Reviews of geoengineering techniques have emphasised that they are not substitutes for emission controls and have identified potentially stronger and weaker schemes. However, such is the lifetime of some greenhouse gases in the atmosphere, most notably carbon dioxide, that geoengineering represents the only currently known method for reducing Earth's temperature in the short term (years----decades). Proposed strategies of Geoengineering Solar radiation management: reduce the net incoming short-wave (ultra-violet and visible) solar radiation received, by deflecting sunlight, or by increasing the reflectivity (albedo) of the atmosphere.-Surface based (land or ocean) albedo modifications-Troposphere based (cloud albedo modification)-Upper atmosphere based-Space based (mirrors in space)Co2 Removal: Creating biochar (anaerobic charcoal) and burying it to create terra pretaBio-energy with carbon capture and storage to remove carbon and simultaneously provide energyCarbon air capture to remove carbon dioxide from ambient airOcean nourishment including iron fertilisation of the oceansHeat Transport: The use of vertical ocean pipes to mix cooler deep water and warmer surface water has been