Louisiana Environmental Action Network

LEAN and the Global Warming Issue

Louisiana ranks ninth in the United States in carbon dioxide emissions, EPA data. If Louisiana were a country it would rank 25th in carbon dioxide emissions in the world and be ranked between Turkey and the Netherlands.

LEAN's Position

We want to introduce legislation in the 2008 legislative session to adopt regulations requiring Louisiana's industries to report the amount of greenhouse gases they emit. The development of an emissions baseline is a necessary first step in the control of greenhouse gas emissions. If you would like to help in this legislative effort please sign up. Sign Me Up

Some Global Warming Facts and Data

Recent scientific results show that temperature changes on the Earth follow variations in Earth's orbit around the Sun. The temperature variations occur in 100,000 year cycles which are not fully understood but are thought to be associated with Milankovitch Cycles.

Figure 1. Temperatures in the Antarctic over the last 420,000 years. Data is from NOAA .

The current time is year zero on the graph. The lower temperatures are ice ages and the higher temperatures are warmer periods such as the one we're in now. Today's warming period started about 12,000 years ago and is called the Holocene Period. Due to glaciers building up and melting ocean levels rise and fall by over 100 yards as the ice ages come and go. 

Question 1. Have humans changed Earth's atmosphere?

Significant changes to earth's atmosphere have occurred in the last 150 years. The only plausible explanation is that these changes are the result of human activity during the industrial age. Carbon dioxide, CO2, is 30% higher than at any time in the last 420,000 years and methane, CH4, has gone off the charts.

Figure 2. Carbon dioxide and methane in Earth's atmosphere in the last 420,000 years. The right side of the graph is greatly expanded to show the increases in the last 150 years. The graph is from J. Hanson.

Question 2. What does this mean?

That's the big question, what if anything will these changes to our atmosphere mean? The best estimates come from computer models that have been run by research groups throughout the world. These models all predict that global temperatures will continue to rise as long as humans keep releasing carbon dioxide to the atmosphere.

Figure 3. Future temperature estimates due to global warming. The data is from IPCC page 14 (Intergovernment Panel on Climate Change).

The brown line predicts what would happen if human emissions were  limited to the amount released in the year 2000. The red, green and blue lines are predictions of temperature rise due to increases in emissions above those in the year 2000.

Impacts on Louisiana

Ocean levels have been rising due to recent increases in the global temperature. Increasing sea levels create obvious problems for Louisiana including coastal losses, wetlands, New Orleans and other low lying population areas. Louisiana has already seen the damage record hurricanes can cause. Louisiana would also share in global warming problems affecting other areas, such as reductions in California crops due to the drier, hotter temperatures expected there or increased storms, floods and droughts expected throughout the United States.

What We Know, Some Amazing Science in Action

• Proxy Data. Modern laboratory equipment can get accurate data about Earth's past from what is called proxy data. Proxy data is data from natural recorders of climate variability such as tree rings, ice cores, fossil pollen, ocean sediments, coral and historical data.
  
  
• Vostok Ice Core. The most well known ice core data is from the Vostok ice core. An oil drilling rig was taken to the middle of Antarctica and a 2.5 mile well was drilled. The ice from the well bore was then then used to determine what Earth's atmosphere was like in the last 420,000 years. But scientists weren't just after atmospheric data, they are drilling into the world's seventh largest lake, called Lake Vostok (More on Vostok Drilling ). Scientist would like to find out if there is anything living in Lake Vostok but have stopped a few hundreds yards short of the lake because they don't currently know how to take samples without contaminating the lake with bacteria and other microbes from the surface.
  
  
• Gravity data. NASA has GRACE (Gravity Recovery and Climate Experiment) which uses two identical spacecraft orbiting the earth 220 kilometers apart. GRACE was built to measure changes in earths gravity field and does this so exactly that it can tell how much glaciers in Greenland and Antarctica are melting each month.

Figure 4. Monthly changes in the mass of Greenland's ice sheet coverage observed by the Grace satellites during 2005. Purple and dark blue areas indicate areas of largest mass loss.  Data is from the NASA.

• Solar Data. Scientists have been able to piece together solar data back to the 1650's when solar activity was much less than today. Combining this historical data with data from today's satellites and telescopes scientists have concluded that increased solar activity has increased Earth's temperature but these increases are only a small amount of the total temperature increase in recent years.

Figure 5. The blue line shows changes in Earth's temperature predicted from just solar activity. The brown line shows the actual temperature changes.

This data shows that solar activity can't account for the recent temperature increases. Data is from the Max Plank Institute for Solar System Research.

The Global Warming Blame Game: Did Not! Did Too! by Steve Fleischli