Posted July 19th, 2009 in Physics. Tags: Climate, Conversation, Diagrams, Intermediate-Science, No Equations, Physics, Pseudoscience.
One part of a recent survey caught my attention:
The strongest correlate of opinion on climate change is partisan affiliation. Two-thirds of Republicans (67%) say either that the Earth is getting warmer mostly because of natural changes in the atmosphere (43%) or that there is no solid evidence the Earth is getting warmer (24%). By contrast, most Democrats (64%) say the Earth is getting warmer mostly because of human activity. … The divide is even larger when party and ideology are both taken into consideration. Just 21% of conservative Republicans say the Earth is warming due to human activity, compared with nearly three-quarters (74%) of liberal Democrats. [Pew Research Center] (Skip to videos, data, index.)
In other words, most of the general public appears to believe that the existence of abrupt climate change A large-scale change in the climate system that takes place over a few decades or less, persists (or is anticipated to persist) for at least a few decades, and causes substantial disruptions in human and natural systems. (formerly known as anthropogenic ‘Human-caused’ global warming) is a question of politics rather than science. (more…)
Posted April 7th, 2012 in Physics. Tags: Climate, Diagrams, Intermediate-Science, No Equations, Pedagogy, Physics, Quickie.
The overwhelming majority of scientists endorse this statement:
“Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.” [IPCC Summary for Policymakers, 2007]
Here, “most” means at least 50% of the 0.55°C rise since 1950. Some mistakenly call this an “alarmist exaggeration” but it actually understates the human contribution because it’s easy to incorrectly conclude that the other 50% of the trend might be caused by natural forcing variations: (more…)
Posted February 9th, 2013 in Science. Tags: Climate, Diagrams, Graphics, Introductory-Science, No Equations, Pedagogy, Physics.
Before the Industrial Revolution in the 1800s, the concentration of carbon dioxide (CO2) in the atmosphere was about 280 parts per million (ppm). This means that for every million molecules in the atmosphere, about 280 of them were CO2.
However, climate.nasa.gov shows that we’ve burned so much coal and oil that atmospheric CO2 is now approaching 400 ppm. It hasn’t been this high for millions of years. The last time Earth’s atmosphere had this much CO2, our species (and many others) hadn’t yet evolved. (more…)