Monitoring and 
 
 Diagnostics 
 
 Laboratory 
 
 ; atmosp 
 constituents that ca 
 affect the Earth's clima 
 
 m 
 
 N0M19 19 98 
 
 ^"oepoatorv 
 
 Boulder, Colorado 
 
Greenhouse Gases Increasing , What About the Sun? 
 
 Atmospheric greenhouse gases pass solar lighl 
 absorb some of the Earth's heat thereby provi 
 a livable planet. Increases in these gases will < 
 the Earth to warm. Of those greenhouse g 
 are undergoing change, carbon dioxide is 
 important. It is a byproduct of fossil fuel burning 
 thus larger concentrations are observed in the 
 northern hemisphere (see above). 
 
 Methane is another important growing greenhouse 
 gas which has numerous sources. Its global rate of 
 growth (see below) has been declining recently but 
 shows large variations. 
 
 The ability of the atmosphere to absorb visible 
 solar radiation has been monitored at Mauna 
 Loa Observatory since 1957 (see above). 
 These measurements reveal the effects of 
 major volcanic eruptions, which deposit 
 particles in the stratosphere and interfere 
 
 ..and Aerosol Particles? 
 
 tmospheric haze in the Arctic due to polk 
 ecreased during the 1930's but has been I 
 •ince (see below). Such particles are capab 
 loth backscalterins and absorbing solar rac 
 
 
 
, Boulder, CO 
 " Islind.VA 
 
 1985 1990 1995 
 
 ne layer in the stratosphere protects living 
 ns on Earth from harmful solar ultraviolet 
 >n. The ozone layer has declined across the 
 tudes of the United States by 7% over the 
 years (see above). 
 
 arctic ozone hole was first discovered in 
 id has now grown to huge proportions 
 ■ iutal destruction of ozone in the 14-20 km 
 i-13 mile) altitude region (see below). Declining 
 levels of ozone-destroying gases in the atmosphere 
 are a harbinger of ozone recovery, expected to 
 begin early next century. 
 
 Global Cooperative 
 Sampling Network 
 
 Through international cooperation, 
 
 air samples containing greenhouse 
 
 gas and ozone-destroying chemicals, 
 
 are collected at over 50 sites around 
 
 the globe. These measurements 
 
 CFCs Have Turned Over! 
 
 5 10 15 
 
 Ozone Concentration 
 
 m-i iuay ma m/ 
 
 ocarbons (CFCs) initiated by the 
 Protocol on ozone-depleting gases, 
 
 ■pheric concentration of some of these 
 ihas begun to decrease (see above), 
 
 J for the ozone layer and the science 
 
 applications, for example in refrigeration and 
 insulation, have been replaced by HCFCs which 
 are much less harmful to ozone and, while at 
 low levels, are increasing dramatically (see 
 below). In the future, even more ozone-friendly 
 replacements must be found. 
 
 Q-a u y iViamiuJih Am brizm 
 
 South Pole>^fitarctica | 
 
Intergovernmental Panel on 
 Climate Change (IPCC) 1995: 
 
 "The balance of evidence 
 
 suggests a discernible human 
 
 influence on global climate" 
 
 The Forcing Elements of 
 Climate Change 
 
 Very Very Very Very 
 
 The Climate Monitoring and Diagnostics Laboratory 
 (CMDL) contributes to the IPCC Climate Change 
 Assessments by conducting research related to 
 atmospheric constituents that are capable of forcing 
 change in the dim 
 
 modification of the atmospheric radiative 
 environment, and those that may cause depletion of 
 the global ozone layer. CMDL accomplishes this 
 mission primarily through long-term measurements 
 of greenhouse gases such as carbon dioxide, carbon 
 monoxide, methane, nitrous oxide, surface and 
 stratospheric ozone, CFCs and their replacements, 
 and aerosols and solar and infrared radiation at 
 
 Contact CMDL at: (303) 497-6074 
 325 Broadway, Boulder, CO 80303 
 
 ADDDD331ESlfl3