Sea Level Last updated 09.16.08
The chart on the left shows historical sea level data derived from 23 tide-gauge measurements. The chart on the right shows the average sea level since 1993 derived from global satellite measurements, updated here monthly. Sea level rise is associated with the thermal expansion of sea water due to climate warming and widespread melting of land ice.
For access to complete oceanography data sets, visit NASA's Physical Oceanography Distributed Active Archive Center.
Ice Mass Last updated 09.18.08
This illustration on the left shows areas where ice melt occurred for more than three days over Greenland during 2007. Areas in which melt occurred for longer time periods are shown in a darker red while those areas melted for fewer days are shown in lighter red.
Carbon Dioxide Concentration Last updated 09.16.08
Carbon dioxide (CO2) is an important greenhouse gas released through natural processes such as respiration and volcano eruptions and through human activities such as deforestation and burning fossil fuels. The chart on the left shows the historical levels of CO2 in the Earth's atmosphere. The chart on the right shows CO2 levels in recent years (corrected for average seasonal cycles).
Global Average Temperature Last updated 05.19.08
The time series shows the combined global land and marine surface temperature record from 1850 to 2007. The year 2007 was eighth warmest on record, exceeded by 1998, 2005, 2003, 2002, 2004, 2006 and 2001.
Ozone Hole Last updated 09.18.08
Ozone concentration for Sept. 11, 2008
Source: JPL/NASA |
Latest size: 27 million square km (10.4 million square miles)
Record size: 27.4 million square km (10.6 million square miles)
(Sept. 7-Oct. 13 average)
The "ozone hole" is a severe depletion of the ozone layer high above Antarctica. It is primarily caused by human-produced compounds that release chlorine and bromine gases in the stratosphere. The ozone layer acts to protect life on Earth by blocking harmful ultraviolet rays from the sun.
The image at left is a view of the most recent Antarctic ozone hole, derived from satellite measurements that monitor the ozone layer. The blue and purple colors are where there is the least ozone, and the greens, yellows, and reds are where more ozone is present.
There are signs that ozone depletion is slowing in response to the 1987 Montreal Protocol, which resulted in a significant reduction in global emissions of ozone-depleting chemicals. However, climate change may cause the ozone hole to expand further. |
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