Understanding the causes for changes in the weather day to day and year to year can be difficult because the complex systems underlying weather and climate change are not completely understood--but here is some information to help you differentiate between the two.

Weather is:

☼ The state of the atmosphere at a given time and place, with respect to variables such as temperature, moisture, wind velocity, and barometric pressure.

Climate is:

☼ The meteorological conditions, including temperature, precipitation, and wind, that characteristically prevail in a particular region; Weather averaged over a long period of time.

 ☼ Regional Climate: The average weather in a place over more than thirty years. Regional climate is  often described by the temperatures over the seasons, how windy it is, or how much rain and snow fall.

☼ Global Climate: Description of the climate of a planet as a whole, with all the regional differences averaged.  Global climate depends on the amount of energy received by the sun and the amount of energy that is trapped within the system.

                  

Are recent extreme weather events due to global warming?

    ☼ It is not possible to link any particular event definitiely to global warming, but as the world warms more of some types of extreme events are expected (heat waves, heavy precipitation, blizzards, and droughts.

Does climate change?

    ☼ Yes, significant changes in the Earth's climate have occurred in the past and are likely to occur in the future.

"The Earth's climate has changed drastically, and often over geological time. All of the reasons for these changes are not completely understood, but we know that climate change predates human history. Many theories have been advanced to explain these climate changes, including theories about changes in the sun's energy output, the Earth's orbit, volcanism, meteorite showers and most recently "the greenhouse effect."

(http://www.globalwarming.org/article.php?uid=114)

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Is Global Warming already occurring?

    ☼ Yes, The IPCC concluded in its Third Assessment Report, "An increasing body of observations gives a collective picture of a warming world and other changes in the climate system." The kinds of changes already observed that create this consistent picture include the following:

• Increase in global average surface temperature of about 1°F in the 20^th century
   
• Decrease of snow cover and sea ice extent and the retreat of mountain glaciers in the latter half of the 20^th century
   
• Rise in global average sea level and the increase in ocean water temperatures
   
• Likely increase in average precipitation over the middle and high latitudes of the Northern Hemisphere, and over tropical land areas
   
• Increase in the frequency of extreme precipitation events in some regions of the world

Examples of observed physical and ecological changes:

• Thawing of permafrost
   
• Lengthening of the growing season in middle and high latitudes
   
• Poleward and upward shift of plant and animal ranges
   
• Decline of some plant and animal species
   
• Earlier flowering of trees
   
• Earlier emergence of insects
   
• Earlier egg-laying in birds

(http://www.ucsusa.org/global_warming/science/global-warming-faq.html#4)

Is current weather getting more extreme?

    ☼

What will happen in the future?

    ☼ Cannot be determined.

"No one knows for certain. However, one can expect hurricanes, tornadoes, floods and droughts to be similar in intensity and frequency to those that have occurred in the past. Also, because world population is growing and people are building in previously uninhabited areas, world governments, weather sensitive industries and others need to prepare to handle extreme weather events. Catastrophic extreme weather events will continue regardless of whether or not climate change occurs. Additionally, research is needed to improve climate models as well as our understanding of the factors that influence climate. Observational studies also are needed in order to better document the Earth's variable climate."

(http://www.globalwarming.org/article.php?uid=114)