Caption for Image 1: Unusually low solar activity between 1645-1715 likely triggered the 'Little Ice Age' in regions like Europe and North America. A lag time of arguably 10-30 years allowed for the climate system to be affected by an increased ozone layer that altered the heating of the oceans. According to the model, diminished jet stream winds caused by a dimmer sun created cold land temperatures by reducing the transport of warm Pacific air to America and warm Atlantic air to Europe. During this shift, winter temperatures cooled as much as 2 to 4 degrees F - enough to freeze rivers and alter agriculture, economy, disease, etc.
Pictured is the climate model used by researchers to watch temperature anomalies. As such, 1780 was used as an arbitrary baseline; the ice age period, then, is colder/bluer and 1780 is white or neutral. Redder colors in more modern times reflect warmer temperatures. Credit: NASA
Caption for Image 2: The Sun shows signs of variability, such as its eleven-year sunspot cycle. In that time, it goes from a minimum (seen here in 1996) to a maximum (2000) period of activity that affects us everyday. When particularly active, solar storms can spew tons of radiation to Earth in the form of Coronal Mass Ejections (CMEs) that can affect power grids, spacecraft, and communication systems. Credit: NASA / ESA
Caption for Image 3: The lack of activity on the Sun was strongly felt during the Little Ice Age, yet scientists credit greenhouse gases and global warming with having such an impact on us today. Most experts point to 1850, start of the industrial age, to when the major influence of climate started to shift from the Sun to ourselves. Click on the image to take you to the NASA Carbon Cycle Initiative site. In the first graph on the site, a flat line reflects steady carbon measurements prior to 1850. The other graphs show a stable increase of ambient carbon dioxide oscillating as a general trend, but still rising and falling with seasonal change. Credit: NASA / ORBIMAGE
Caption for Image 4: This computer model shows the dispersion of the volcanic plume from the Mt. Pinatubo volcano. The 1991 Pinatubo eruption was sulfur-rich, producing volcanic clouds that lasted a number of years in the stratosphere. The Pinatubo eruption widely expanded the area of ozone loss over the Arctic and Antarctic. Red colors indicate higher elevations and blue colors indicate lower elevations for the plume. Credit: NASA
Caption for Image 5: The eruption of Mt. Pinatubo blasted a huge cloud of sulfur dioxide, shown in red, into the stratosphere. This data taken from NASA's Total Ozone Mapping Spectrometer (TOMS) instrument shows that initial burst of sulfur dioxide and its international path in the days following the eruption, from June 16th to June 30th. The sulfur gas cloud dissipates as the gas turns into droplets of sulfuric acid. Both the gas and subsequent acid were contributors to the overall dust cloud that cooled the global climate. Image Credit: NASA
Caption for Image 6: During the year and a half after the eruption, global stratospheric ozone levels decreased as a result of chemical reactions with the ozone and the sulfur dioxide gases released by the volcano. However, the initial effect of the injection of sulfur dioxide into the atmosphere was so strong, that a small hole was created in the ozone layer, (from June 15th, 1991 through June 30, 1991) as seen here, in blue, using TOMS data. This visualization shows global ozone levels before and after the eruption. After the hole dissipates, continued low levels of ozone, in very light blue, can be seen around the tropics. Credit: NASA
Caption for Image 7: The Arctic Ozone "Hole" The blue colors in this sequence depict the depleted region of ozone over the North Pole that occurred in the winter of 2000. Though ozone "holes" appear each year over the South Pole, low levels of ozone only occasionally form over the northern polar regions during very cold winters. Scientists say the northern ozone hole may reappear for several consecutive years after a period of high volcanic activity. A northern ozone hole could be significant because more people live in Arctic regions than near the South Pole. The data for these images were collected by the Total Ozone Mapping Spectrometer (TOMS) satellite.Credit: NASA