When?

Q: When do people need to act more sustainably?

A: By quickly reaching higher levels of sustainability, people will avoid problems that would make achieving a sustainable condition more difficult. For example, getting pollutants like plastic out of oceans, rivers and lakes maybe impossible. Reducing single use plastics, recycling, and preventing release of waste to the environment are steps we can easily take to limit how much worse the build of poolutants gets.

Q: When did we start to see the effects of human action on the climate?

A: Answer needs to be developed

Q: When did the amount of greenhouse gases in the atmosphere get to be too high?

A: From about 1950 to about 1990, atmospheric carbon dioxide concentations went from about 300 parts per million (ppm) to about 350 ppm.  Prior to 1950, carbon dioxide concentrations hadn't exceeded 300 ppm for hundreds of thousands of years.  Many scientists consider 350 ppm to be the upper acceptable limit.  Carbon dioxide is one greenhouse gas; others, especially methane, are also very significant.  Therefore, it can be concluded that greenhouse gases in the atmospere got to be too high before 1990.  

Carbon emissions increased dramatically from 1950 to 2013. We need to reduce carbon emissions - ultimately to zero - and then work on net removal of greenhouse gases to get atmosheric greenhouse gas levels back down to levels last observed in the 1980s.

http://cdiac.ornl.gov/images/global_fossil_carbon_emissions_google_chart.jpg

Q: When did people start to understand that fossil fuel combustion could impact the climate?

A: Answer needs to be developed

Q: When can I start start making a difference?

A: Answer needs to be developed

Q: When should I have conversations about sustainability?

A: Answer needs to be developed