Are persistent contrails and aviation pollution geoengineering our skies? You be the judge.

Are persistent contrails and aviation pollution geoengineering our skies? You be the judge.

This article contains reference material for those interested in chemtrails (internet slang for “chemical-trail” or the invisible exhaust particulates released from jet aircraft engines), which contribute to the formation of persistent contrails (spreading, man-made clouds that cool the planet during the daytime and trap heat at night). • 


Impact of Aviation on Climate Change

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A round trip flight from New York to Los Angeles releases as much C0₂ as one automobile does in an entire year. On a yearly basis all air travel releases 600 million tons of carbon dioxide into the atmosphere. 1 round trip flight from NY to LA = 2,000 pounds of CO₂!
earthlyissues.com

Evaluating the Impacts of Aviation on Climate Change (AGU)

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• Increased urgency to deal with factors affecting climate change
  
• Climatic changes include
  
  
  
  • Direct emissions: CO₂, Water vapor and other greenhousegasses (GHG) (best understood)
    
  • Indirect effects: NO_x affecting distributions of Ozone andMethane (Ozone and Methane effects have opposite signs)
    
  • Effects associated with contrails and cirrus cloud formation
    
  
  
• Aviation responsible for 2% of all anthropogenic CO₂ emissions
  
• Large uncertainty in the understanding of the impact of aviation on climate change
  

Workshop on the Impacts of Aviation on Climate Change: A Report of Findings and Recommendations • June 7-9, 2006, Cambridge, MA

Contrails

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• Aircraft condensation trails occur when warm engine exhaust gases and cold ambient air interact • [Ice-Supersaturated Regions (ISSR)]
  
  
  
  • Contrails form when Relative Humidity with respect to Water (RHW) >Temperature dependent threshold
    
  • Persist when Relative Humidity with respect to Ice (RHI) >100%
    
  
  
• Contribution of contrails to global warming may be larger than contribution from CO₂ emissions
  

Atmospheric science: Seeing through contrails

Satellite infrared images of contrails spreading into cirrus clouds over the UK

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The young contrails, which appear as a spring shape and sharp lines in the first image, gradually spread into cirrus clouds, which appear as bright white areas in the lower images.

Research Projects & Tools
Future Aircraft Traffic Management Concepts Evaluation Tool (FACET) • [PDF]

• Aviation Climate Change Research Initiative (ACCRI)
  
• Centre for Aviation Transport and the Environment (Omega)
  
• Formation flying civilian airliners?
  
• NASA Langley Cloud and Radiation Group
  
  
  
  • Satellite Imagery and Cloud Products
    
  • Field Experiments
    
  • Also see: NASA WorldView
    
  
  
• Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO)
  
• Next Generation Air Transportation System (NextGen)
  
  
  
  • Performance Based Navigation (PBN) Dashboard
    
  
  
• FAA Aviation Environmental Tool Suite
  
  
  
  • Aviation Environmental Design Tool (AEDT) • aedt.faa.gov • [url=http://www.faa.gov/about/office_org/headquarters_offices/apl/research/models/history/media/Davis_Breaking Barriers_AEDT.pdf][PDF][/url]
    
  • Environmental Design Space (EDS)
    
  • Aviation environmental Portfolio Management Tool (APMT) • mit.edu
    
  • Legacy
    
    
    
    • Emissions and Dispersion Modeling System (EDMS)
      
    • System for Assessing Aviations Global Emissions (SAGE)
      
    • Model for Assessing Global Exposure to the Noise of Transport Aircraft (MAGENTA)
      
    
    
  
  
• Climate compatible Air Transport System (CATS)
  
• Climate Optimized Routing of Flights
  
• Environmentally Responsible Aviation (ERA)
  
• Sustainable Alternative Jet Fuels
  
  
  
  • Jet Biofuel Enlisted For Contrail Control
    

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    The space agency recently began doing flights over the Southern California desert in which a DC-8 “flying laboratory” is testing the contrail consequences of using standard JP-8 jet fuel versus a 50-50 blend of JP-8 and a biofuel made from camelina plants.

  • INCITE Researchers Explore How Aircraft Contrails Can Impact Climate
    
  • (ACCESS) Alternative-Fuel Effects on Contrails and Cruise EmiSSions flight schedule
    
  • The Commercial Aviation Alternative Fuels Initiative (CAAFI)
    
  • Continuous Lower Emissions, Energy, and Noise (CLEEN) Program
    
  • Alternative Aviation Fuels Broad Agency Announcement (BAA)
    
  • Partnership for Air Transportation Noise and Emissions Reduction (PARTNER)
    
  • Airport Cooperative Research Program (ACRP)
    
  
  

Black Arctic Highways

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The black stuff on the bottom of the lakes is carbon dust and pollution in general… but not from one year, but several decades (the topographical conditions don’t change from year to year). On a flight over the Ice Cap a sky clear day, you can see hundreds of huge lakes with the black spot on the bottom.
Greenland Ground Zero for Global Soot Warming

Carbon Black Dust

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Even before soot gets far into the air, it has a particularly harmful effect: it makes people sick. In recent days, news reports from China have provided startling images of Beijing swaddled in a blanket of sooty smog. That air pollution, from cars and coal-fired plants, takes a terrible toll on the country’s health. Far from the world’s urban centers, poor people suffer from air pollution in their own homes when they cook with smoky stoves and breathe in black carbon and other pollutants.
These benefits of cutting black carbon were already apparent before Doherty and her colleagues published their new study; now it’s clear that cutting soot could help not just personal health, but planetary health as well.
Black Carbon and Warming: It’s Worse than We Thought

• The Double-Sided Sensitivity of Clouds to Air Pollution & Intentional Seeding • [PDF]
  
• Is the indirect forcing by aircraft soot positive or negative? • [PDF]
  
• A bit of a bombshell from the AGU IGBR: Black carbon is a larger cause of climate change than previously assessed • [Link]
  
• On the possibility of weather modification by aircraft contrails • [PDF]
  
• Weather Modification by Carbon Dust Absorption of Solar Energy • [PDF]
  
• Weather as a Force Multiplier: Owning the Weather in 2025 • [PDF]
  
• US Army Test Technology Symposium – Weather Modification 1997 • [Link]
  
• Operational Weather Control in 2030 • [PDF]
  

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  The United States needs to incorporate the defense against directed energy weapons with the same intensity used developing anti-ballistic missile defenses. One of the major drawbacks to optical or directed energy systems is the inability to penetrate clouds or dense fog. Advances in technology are beginning to bring weather phenomena under our control. Greatly increased computing power and micronized delivery systems will allow us to create specific perturbations in local atmospheric conditions. These perturbations allow for the immediate and lasting ability to create localized fog or stratus cloud formations shielding critical assets against attack from energy based weapons. The future of nanotechnology will enable creation of stratus cloud formations to defeat DEW and optically targeted attacks on United Sates assets. The solution the weather control problem involves networked miniature balloons feeding and receiving data from a four-dimensional variation (4d-Var) computer model through a sensor and actor network. A network of diamond-walled balloons enters the area to be changed and then both measures and affects localized temperature and vapor content. This system effectively shortens the control loop of an atmospheric system to the point it can be managed. The capabilities in the diamond-walled balloons are based on the future of nanotechnology.

Energy Efficient Contrail Mitigation Strategies for Reducing the Environmental Impact of Aviation [PDF]
Tenth USA/Europe Air Traffic Management Research and Development Seminar (ATM2013) • Chicago, Illinois, 10-13 June 2013 [Papers and Presentations for Seminar 10]
There is increased awareness of aviation-induced environmental impact affecting climate change [1]. Estimates show that aviation is responsible for 13% of transportation-related fossil fuel consumption and 2% of all anthropogenic CO2 emissions [2]. Although emission contributions from aviation are small, a large portion of the emissions takes place at altitudes where the emissions remain longer in the atmosphere than if emitted at the surface. After a small decline over the last few years, air traffic has increased since 2011, and the Federal Aviation Administration (FAA) expects domestic air traffic to grow at an annual rate of 3.5% over the next 20 years [3]. Global air traffic is expected to grow more rapidly than domestic air traffic at an annual rate of 4.8% from 2011 to 2030 [4]. The desire to accommodate growing air traffic needs while limiting the impact of aviation on the environment has led to research in green aviation with the goals of better scientific understanding, utilization of alternative fuels, introduction of new aircraft technology, and rapid operational changes.
Aviation operations affect the climate in several ways. The climate impact of aviation is expressed in terms of “radiative forcing” (RF). RF is a perturbation to the balance between incoming solar radiation and outgoing infrared radiation at the top of the troposphere. The amount of outgoing infrared radiation depends on the concentration of atmospheric greenhouse gases (GHG). RF associated with each type of emission has an approximately linear relationship with global mean surface temperature change. CO2, water vapor, and other gases are unavoidable by-products of the combustion of fossil fuel; of these CO2 and water vapor are GHG resulting in a positive RF. Because of its abundance and long lifetime, CO2 has a long-term effect on climate change; the non-CO2 emissions have a short-term effect on climate change. The important non-CO2 impacts associated with aviation are water vapor, oxides of nitrogen (NOX), condensation trails (contrails) and cirrus clouds due to air traffic. Contrails are clouds that are visible trails of water vapor made by the exhaust of aircraft engines [5]. The latest estimates indicate that contrails caused by aircraft may be causing more climate warming today than all the residual CO2 emitted by aircraft [6].
Concluding Remarks

Initial results demonstrate that a contrail reduction policy involving altitude changes to aircraft flying distances greater than 500 miles applied on days with high contrail activity is more energy efficient than applying altitude changes to avoid contrails to all aircraft on all days. These results need to be evaluated further with a range of values covering uncertainties in contrail formation and RF associated with contrails.