 Myth: What global warming? Earth has actually been cooling since ◦ 1998 was the warmest summer  It’s been cooler since then ◦ Not supported by scientific data  Instead shows that there has been a “warming trend” ◦ Scientist say:  1998 was not the warmest summer  Seasons have been cooler due to natural disasters

 Myth: Physicist Ferenc Miskoczi and other scientists claimed that increasing the carbon dioxide won’t make a difference in absorbing more heat.  The idea was put to the test by taking a small tube and putting CO2 in it and infrared light was put through it and then with water vapor  They then cut the amount of CO2 in the tube by one third and found no difference in the amount of harm it made  but the flaw of the test is that the atmosphere is thicker and more complicated than the tube and that at the top of the atmosphere CO2 keeps the heat in and lets little out.

 Clouds are very complex. They hold in heat from the surface. The atmosphere is divided into blocks larger then clouds. Therefore climate modelers have a hard time incorporating clouds.  Aerosols are also hard to model.  Models get the basic patterns correct; differences come in amounts.  When researchers remove man made greenhouse gasses from climate models, temperatures stayed the same.

 Myth: There have been big climate changes in the past, such as the Little Ice Age and the Medieval Warm Period, so why can’t recent climate changes just be explained by natural variability?  People who dispute evidence of recent global warming sometimes point out 2 events that occurred in the past such as The medieval warm period and the little ice age.  Our current warming is just an unlucky minor shock rather than a long term trend.  Climate scientist now understand that medieval warm period was caused by an increase in solar radiation and a decrease in volcanic activity, along with currents bringing warmer water to North Atlantic.

 The heat at Earths surface comes from radiation from the sun. -Radiation more intense means warmer planet.  Cosmic rays help form water droplets and clouds. ◦ Clouds are thought to cool off the planet. So if the sun is more active, and fewer cosmic rays, less cloud cover equals to warmer Earth.

 Myth: The urban heat island effect or other land use changes can explain the observed warming.  Urban heat island effect - caused by roads and buildings absorbing more heat then plants  It causes the cities to be warmer and can also cause rainfall patterns  Not true because some of the greatest areas of warming are in rural, not urban areas.

 Myth: Natural ocean variability can explain the observed warming  The oceans are the largest single reservoir of heat in the climate system.  The internal cycle of variability change the seas temp. from decade to decade, so it’s thought that we’re in a warm period that will last a few decades.  The top 100 meters of the ocean are in a trend of high temp. across the planet. When that happened before it was only at Antarctica.  It cannot be explained by any known ocean cycles.

 Myth: In the past, global temperatures rose first and then carbon dioxide levels rose later. Therefore, rising temperatures cause higher CO2 levels, not the other way around.  So, CO2 increases are caused by global warming, not the other way around.  During glacial (cool) periods on Earth, atmospheric CO2 levels are lower and during interglacial (warmer) periods, CO2 levels are higher  The role of CO2 in natural glacial/interglacial climate change is to amplify the climate change making warmer periods somewhat warmer  CO2 and temperature actually rose together for about 90 percent of the time—doesn’t mean CO2 isn’t causing increase now.

 Muller on his skeptical BEST  Skeptic about global warming… so he made a study so that he can prove it himself  Previous studies show global warming is caused by… 1. Heat island effects 2. Poor station quality 3. Working with small subset stations 4. adjustments to data  Concluded in the past 50yrs temps. Of the surface increases 1.8 degrees F.  What he analyses was information from other scientist his OWN analysis is a great contribution to be able to understand global warming.

 Remarks from a Climate detective  Ben Santer was trying to identify the causes of climate change over the last 50 years. Him and his colleagues used global climate data and global model simulations by looking for telltale patterns of “fingerprints” variations. Due to an uptick in solar output it leads to warming of entire atmospheric column. This type of study shows how human influence on global climate. Others say greenhouse gas concentrations.

 The Upshot: Wishful hearing?  Muller went to a meeting at Committee On America’s Climate Choices. After the presentations, the talk turned to the role of humans and global ideas that had no clear evidence. He was skeptical that the briefing lived up to his name. He said he wouldn’t hold his breath waiting a congressional resolution marking the end of climate skepticism.