Global warming

There are many theories surrounding the causes for global warming, but the main and proven reason is the effect of greenhouse gases that are emitted into the atmosphere.  It has been due to the increase in the atmosphere of greenhouse gas concentrations like water vapor, carbon dioxide (CO₂), methane and ozone.  The largest contributor of the greenhouse effect are fossil fuels being burned which then emits carbon dioxide into the air.

When sunlight reaches Earth's surface, some is absorbed and warms the earth, but the rest usually is radiated back to the atmosphere at a longer wavelength than the sun light. Some of these longer wavelengths are absorbed by greenhouse gases in the atmosphere before they are lost to space. The absorption of this long wave radiant energy warms the atmosphere.  Because of this the greenhouse gases then radiate the heat back to the earth and cause the "global warming" effect due to the fact that the heat trapped by the gases could not be released back into space.

http://timeforchange.org/cause-and-effect-for-global-warming
http://news.ufl.edu/2012/01/09/glacial-patterns/
http://climate.nasa.gov/causes

Solar flares

A flare is defined as a sudden, rapid, and intense variation in brightness. A solar flare occurs when magnetic energy that has built up in the solar atmosphere is suddenly released.  Solar flares can vary in length and time, although scientists have found ways to calculate when one will occur and its basic effect.  These solar flares alter the balance of the earth because of the massive magnetic and heat waves that the flares can create.  The amount of energy released is the equivalent of millions of 100-megaton hydrogen bombs exploding at the same time.  Fortunately, the earths magnetic field and atmosphere protect us from the flares dangerous radiation.  

The direct effects of solar flares are mainly related to communications and radio transmissions.  Another effect that solar flares have upon the earth is that of auroras.  When some of the charged particles of the solar flare pass through the earths magnetic field and atmosphere, they get accelerated along the lines of the magnetic field and collide with the particles in the atmosphere which makes them glow. There are also health issues for airline pilots and astronauts. For those of us that spend most of our time on the ground, the magnetic field and the atmosphere block out almost all of the harmful radiation and charged particles. This is not the case when you go up in the atmosphere. Airline pilots that fly at great altitude, and especially near the poles, are exposed to more of these. The same goes for astronauts. This results in a higher incidence of cancer among airline pilots and cabin crew.


http://hesperia.gsfc.nasa.gov/sftheory/flare.htm
http://hesperia.gsfc.nasa.gov/sftheory/spaceweather.htm
http://curious.astro.cornell.edu/question.php?number=308