Summary: The world needs to eliminate 80% of Green House gas (GHG) emissions by 2050 and 100% by 2100 to avoid catastrophic warming. Eliminating 100% by 2100 is necessary because while the oceans have been absorbing increasing man-made GHG's for many years, once the CO2 levels in the atmosphere start to drop the oceans will re-emit those GHG's they previously absorbed until levels balance. US data show no one item as the key source of CO2 (and "equivalent" GHGs like methane and nitrogen oxides) emissions. Personal autos = 18%. ALL Residential use = 19%. Commercial airplane emissions = 3%. ALL farming = 3%.
I am using the US Dept of Energy 2014 World Energy Outlook in reference to US GHG emissions. Notes on data at the end. (
Source links at end).
Green House Gas Emissions by Sector: Looking at the actual emissions it is clear that there is no one end use that is the main contributor to GHG emissions. If we look at each sector in detail, we find only a few large uses, none of which by itself will acheive the 80% reduction in GHG needed. (Click on graphic below to enlarge):
Manufacturing: Manufacturing = 22% of GHG (not including power generation or farming). No one industry can be changed to fix it all. For example, the recent focus on GHG emissions has prompted refineries to use butane and propane for power generation instead of burning it off. This could have been done years ago, but without attention being paid to it, nothing happened. (Click on graphic below to enlarge):
Residential: Heating is the biggest residential GHG emitter, but even that is only 4.2% of total US GHG emissions. Residential lighting is responsible for only 1.8% of GHG emissions. (Click on graphic below to enlarge):
The key point one gets from the residential energy use data is that there is
No. One. Thing. we can do to make a difference. It must be an all-of-the-above effort. Replace gas appliances with electric, put in roof-top solar panels wherever practical, source external power from renewables like wind, wave and utility scale solar with massive banks of back-up electrical storage (batteries, stored hydro, etc.).
Transportation: At 32% of GHG emissions, this is the biggest single contributor to GHG. ALL personal autos (including SUVs, and mini-vans) are responsible for 18% of US GHG emissions - the same as all residential use. Air transport is 3%, including international and transcontinental. (Click on graphic below to enlarge):
We could replace ALL our cars with electric vehicles (an enormous step in the right direction) yet we would not be even close to the 80% reduction in GHG we need.
High Speed Rail is touted as a big saver of energy but even if HSR replaced ALL air travel (including transcontinental and international - a bit unlikely) the maximum 3% decrease (more realistically about 0.5%) in total US GHG emissions is trivial. The many billions spent on building and subsidizing HSR in CA would have a much bigger impact on GHG emissions if it went to extend BART, and the LA Metro-Rail or subsidize solar panels and wind farms. http://en.wikipedia.org/wiki/Metro_Rail_(Los_Angeles_County)
The average American drives 37 miles per day (13,476 miles per year) which at typical bicycle speeds of about 9 miles per hour would mean over 4 hours per day biking to work, shopping, taking kids to soccer and piano lessons, etc. Not going to happen.
The Chevy Volt (below) is a Plug-in Hybrid Electric Vehicle (PHEV).
The Volt can go 40 miles at highway speeds on battery power alone and then switch over to its gasoline-powered engine. This 40 miles covers 80% of typical American daily driving without burning fossil fuels. Volt owners talk of visiting a gas station once every 3 months. Recall that the goal is an 80% reduction of GHG by 2050 to stop global warming. With PHEV's like the Chevy Volt, the Ford "Energi" line, etc., the 80% reduction goal is achieved as far as cars are concerned.
Currently the Volt is $34,000 but a $7,500 federal tax credit and a $2,500 CA credit lower the net price to $24,000. Lowering the price so it no longer needs tax credits along with adding range will be done in 5 years by current battery development. I mention the Volt because it is the only PHEV to achieve the all electric 40 mile range and is currently the most popular PHEV.
Another option is Bio-Fuels. While corn-based ethanol is the most well-known, farmed algae generates 20X the oil per acre as corn, and is easier to refine. It uses salty water and produces pure H2O as a byproduct. Commercial jets have been experimentally flown across the country on 100% algae-derived bio-fuel. The US Navy expects to have a "Green Fleet" operational in 2016 running on bio-fuel blends. Biofuels result in CO2 emissions but since the algae took CO2 out of the atmosphere to make the oil it is "carbon neutral".
Commercial: Commercial use (restaurants, stores, office buildings) generates another 17% of GHG. Nothing jumps out as a big contributor, but clearly every aspect can be electrified with electricity generated by renewable sources. (Click graphics to enlarge)
Miscellaneous: Everything else accounts for 12% of GHG. (Click graphics to enlarge)
That 12% includes much maligned agriculture. Some think that if everyone became vegans and stopped drinking milk, our climate would be saved. Not even close. Farming is 1.2% of GHG emissions and some of that comes from transporting food to the stores. Farm animals emit 25% of the GHG as methane but much of that can be (and sometimes is) recaptured and used for power generation. Of the GHG from dairy farms, 25% is methane, 25% is from transport, and the rest is from farm machinery, lighting, heating, etc.. The dairy industry agreed to cut GHG emissions 25%. Nothing wrong with being a vegan, but it won't do much to stop GHG emissions. (Click picture to enlarge)
The US has a special responsibility to reduce GHG because every man, woman, and child in the US emits more than double the CO2 of any other large country. (Click graphics to enlarge)
The US and Europe have been pouring CO2 into the atmosphere for far longer than other areas and have a special responsibility to do more to clean up.
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| The US and Western Europe (US + EU25 + Germany + the UK + France) are responsible for 73% of the CO2 emitted between 1850 and 2000 |
Our future will be whatever we make it.
Sources:
The data can be confusing because different sources give different numbers. A lot of numbers are educated guesses, and there are wide variances in how to equate different GHGs like methane, CH4, and carbon dioxide, CO2. Some data refers to source (like power plants) , and some to users (like residential use), and some mix them up in a confusing way. For example, electricity generation is sometimes seen as a huge slice of the pie. But electricity is generated for a user and I have focused on that user, since the source will evolve from the centralized plant to be on every farm, house, and office building. In addition, world-wide GHG sources are very different from US sources. Here, the US is the focus. The data from different sources generally agree within 10%.
Source for charts is US Energy Information "Agency Energy Outlook 2014"
http://www.eia.gov/forecasts/aeo/
The data for the charts above are taken from "table 19" downloadable in Excel and PDF format below:
http://www.eia.gov/forecasts/aeo/tables_ref.cfm
List of countries and GHG emission per capita:
http://data.worldbank.org/indicator/EN.ATM.CO2E.PC
How much reduction in GHG emissions is necessary?
- IPCC says 40% to 70% by 2050 and 100% by 2100. Maybe even negative by 2100 - eliminating GHG from the atmosphere that are already emitted: http://www.climatecentral.org/news/major-greenhouse-gas-reductions-needed-to-curtail-climate-change-ipcc-17300
- About 80% by 2050 says a presidential document http://www.climatecommunication.org/wp-content/uploads/2011/08/presidentialaction.pdf
- NYC is committing to 80% reduction by 2050: http://www1.nyc.gov/office-of-the-mayor/news/451-14/mayor-de-blasio-commits-80-percent-reduction-greenhouse-gas-emissions-2050-starting-with#/0
- The World Resources Institue thinks the US can make it 83% by 2050 with aggressive action http://www.wri.org/publication/can-us-get-there-here
Avg US driving mileage:
https://www.fhwa.dot.gov/ohim/onh00/bar8.htm
Avg. bicycle speed:
http://en.wikipedia.org/wiki/Bicycle_performance#Typical_speeds .
Biofuels:
US Navy "Green Fleet"
Capturing methane from dairy farms:
