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Is Global warming real?

Last updated 29 June 2005
Originally answered 19 March 2001

Full Question

Is global warming a real issue that we should be concerned with or is it hype? 

Answer

The threat of global warming is a real issue. It is clear from long-term temperature records that the world is warming. It is becoming clear that human activities, mainly burning fossil fuels and deforestation, are part of the cause of this warming. Since these human activities are expected to continue into the foreseeable future, scientists predict that the earth will continue warming. The debate among scientists who study climate centers around questions like: How much warming? How fast will the earth warm? What will be the regional and seasonal patterns of the warming? What will be the impact of the warming on natural ecosystems and people?

If we can reliably and accurately answer these sorts of questions, we can then make policy decisions to minimize the risk posed by the potential impacts. The controversy, and battles, over global warming arise because these specific questions are not easy to answer, and the policies often have large costs associated with them. Many argue that the costs of taking action is less than the cost of inaction, while groups that might incur the costs of action argue that the uncertainties are too great to make policy changes.

Here are some sites that are good sources of general information on climate change:


The above entry is posted under the following topic(s): Global Change: General

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International data on fossil fuel use and related emissions

Last updated 27 June 2005
Originally answered 18 June 2004

Full Question

How does energy use in the U.S. compare to that of other countries?  How does the U.S. compare to other countries in terms of greenhouse gas emissions? 

Answer

There are several key sources of information that permit international comparisons of energy use and emissions.  Among these are:

  • International Energy Agency
  • Secretariat of the United Nations Framework Convention on Climate Change
  • U.S. Energy Information Administration
  • Carbon Dioxide Information Analysis Center (CDIAC)

The sources, discussed below, vary according to the levels of detail, time periods covered, methodologies, etc.  Using these and other sources, there are many ways to compare the U.S. to other countries.  You can compare total energy use or emissions, compare use of individual fuels, emissions from specific sectors (transportation for example), per capita energy use and emissions, etc.  Using data from the International Energy Agency, we provide in the table below a sampling of comparisons between the U.S., the countries of the Organization for Economic Cooperation and Development (the OECD, which includes most developed countries -- including the U.S.) and the world. 

International Energy Agency

The International Energy Agency collects statistics on energy use from most countries and periodically issues reports that present and analyze the data.  A lot of the information is available online.  For a quick overview, see Key World Energy Statistics -- 2004 Edition (2004) [PDF].  Below are some of the data from that report for the US, the Organization for Economic Cooperation and Development (OECD) and the world.

Selected Energy & CO2 Emissions Indicators for 2002
 
US
OECD
World
Population (million)
287.46
1,145.06
6,195.66
Gross Domestic Product or GDP (billion 95 US$)
9,196.40
28,435.02
35,317.65
GDP (Purchasing Power Parity or PPP) (billion 95 US$)
9,196.40
25,374.85
43,413.48
Total Primary Energy Supply or TPES (Mtoe)
2,290.41
5,345.72
10,230.67
TPES / Population (toe / capita)
7.97
4.67
1.65
TPES / GDP (toe / 000 95 US$)
0.25
0.19
0.29
TPES / GDP (PPP) (toe / 000 95 US$ PPP)
0.25
0.21
0.24
CO2 Emissions from fuel combustion (Mt of CO2)
5,652.30
12,554.03
24,101.83
CO2 Emissions / TPES (t CO2 / toe)
2.47
2.35
2.32
CO2 Emissions / Population (t CO2 / capita)
19.66
10.96
3.89
CO2 Emissions / GDP (kg CO2 95 US$)
0.61
0.44
0.68
CO2 Emissions / GDP (PPP) (kg CO2 / 95 US$ PPP)
0.61
0.49
0.56

Definitions:

  • GDP: Gross Domestic Product
  • TPES: Total primary energy supply (TPES) is made up of indigenous production + imports - exports - international marine bunkers ± stock changes. For the World Total, international marine bunkers are not subtracted from TPES.
  • Mtoe: Million metric tonnes of oil equivalent
  • toe: metric tonnes of oil equivalent
  • CO2: Carbon dioxide
  • PPPPurchasing Power Parity
  • kg: kilogram
  • t: metric tonnes
  • Mt: Million metric tonnes
  • mt:
  • 95 US$: U.S. dollars, 1995
  • OECD: Australia, Austria, Belgium, Canada, the Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Japan, Korea, Luxembourg, Mexico, the Netherlands, New Zealand, Norway, Poland, Portugal, the Slovak Republic, Spain, Sweden, Switzerland, Turkey, the United Kingdom and the United States.

The IEA provides additional online access to Energy Statistics, Energy Balances and Graphs .  For other items, see IEA Publications, CD Roms and Papers.

Secretariat of the United Nations Framework Convention on Climate Change

The Secretariat of the United Nations Framework Convention on Climate Change (UNFCC) maintains Greenhouse Gas Inventory Data,  currently extending from 1990 through 2002.   The information is available as both PDF and Microsoft Excel files.  Unlike the IEA data, it includes not only CO2 emissions but also:

  • CH4 - Methane
  • N2O - Nitrous oxide
  • PFCs - Perfluorocarbons
  • HFCs - Hydrofluorocarbons
  • SF6 - Sulphur hexafluoride
  • CO - Carbon monoxide
  • NOX - Nitrogen oxides
  • NMVOCs - Non-methane volatile organic compounds
  • SOX - Sulphur oxides

The UNFCCC site also provides informative graphics such as:

U.S. Energy Information Administration

While the U.S. Energy Information Administration (EIA) focuses primarily on the U.S., it also produces reports that facilitate comparisons between the U.S. and other countries.  The International Energy Annual includes a set of Microsoft Excel files that provide country-by-country data on CO2 emissions associated with fossil fuel use.  The EIA's International Energy Outlook also is useful in assessing long-term prospects for energy use and related carbon emissions.

Carbon Dioxide Information Analysis Center (CDIAC)

The Carbon Dioxide Information Analysis Center (CDIAC) provides Carbon Dioxide Emissions from Fossil-Fuel Consumption  for major countries and regions, and for the world.  Unlike either the IEA or UNFCCC, the CDIAC data extends back for many years -- to the 18th century for some data sets.


The above entry is posted under the following topic(s): Emissions data and trends

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Climate and Earth's Rotation

Last updated 21 June 2005
Originally answered 11 December 2001

Full Question

What would happen to climate patterns in the world if the Earth’s rotation would go in the opposite direction?

Answer

Although extremely unlikely to ever occur, the hypothetical situation of the Earth rotating in the opposite direction poses an interesting question and prompts a look at how this feature of our planet affects climate.

The rotation of the Earth, which is counterclockwise as viewed from above the North Pole, has many effects on Earth’s weather and climate.

Though not directly related to weather or climate, one of the most obvious results of a reversal in the Earth’s rotation is that the Sun would rise in the west and set in the east.

The Coriolis effect, which results from the Earth’s rotation, plays an important role in large-scale circulation of the atmosphere. As viewed by an observer on Earth, air appears to be deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. This results in areas of low pressure rotating counterclockwise in the Northern Hemisphere and clockwise in the Southern hemisphere, with the opposite being true for areas of high pressure. If the Earth’s rotation were to suddenly reverse itself, these patterns would also be reversed. The westerlies would become easterlies and the northeast trades would blow from the northwest. This would

Changes in the Earth’s rotation would have an effect on ocean currents, which can influence local climates. The El Niño and La Niña phenomena that affect global climate patterns on a periodic basis.

One large component of a location’s climate that would not likely be affected would be the effect of seasons, which are more dependent on the tilt of the Earth’s axis than they are on the Earth’s rotation.


The above entry is posted under the following topic(s): General Earth SciencesClimate (general)

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Difference between climate and weather

Last updated 21 June 2005
Originally answered 18 April 2000

Full Question

What is the difference between climate and weather?

Answer

According to the American Meteorological Society’s Glossary of Meteorology (second edition, 2000), climate is defined as “the slowly varying aspects of the atmosphere—hydrosphere—land surface system.”

This differs from the glossary’s definition of weather, which is “the state of the atmosphere, mainly with respect to its effects upon life and human activities.”

Climate is usually expressed by the statistical collection of weather conditions for a given region during a specific interval of time, usually several decades.

The average value of a meteorological element (e.g., temperature and precipitation) over a 30 year period is defined as a climatological normal. Climate normals help in describing the climate of a location and are used as a base to which observed conditions can be compared. The United Nation’s World Meteorological Organization (WMO) requires the calculation of climate normals every 30 years. The most recent such calculations cover the period of 1961-1990. However, many WMO members, including the United States, update their normals at the completion of each decade. Every ten years the U.S. National Climatic Data Center (NCDC) computes new thirty-year climate normals for selected temperature and precipitation elements for a large number of U.S. climate and weather stations. The most recently computed climate normals produced by NCDC cover the period of 1971-2000.

For a much more detailed discussion, see “What’s the Difference between Weather and Climate,” posted by NASA. 


The above entry is posted under the following topic(s): General Earth SciencesClimate (general)

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Why does climate change?

Last updated 21 June 2005
Originally answered 18 April 2000

Full Question

Why does climate change?

Answer

Climate fluctuations are the result of complex interactions of a number of factors, including natural changes such as variations in the Earth’s orbit (known as Milankovitch theory), volcanic eruptions, fluctuations in solar energy and anthropogenic (human-caused) influences, such as the burning of fossil fuels, which releases so-called greenhouse gases into the atmosphere.

Climate changes can occur over periods as short as a year or as long as several thousand years. For more information, take a look at the following resources:


The above entry is posted under the following topic(s): Global Change ScienceClimate Variability and Change

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