GLOBAL. WARMING. Energy Balance. Energy from the Sun = energy returned to space by Earth’s radiative emission The absorption of solar radiation takes place mostly at the surface of the Earth. The emission of solar radiation to space takes place mostly in the atmosphere.
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When it reaches the Earth's surface, some is reflected back to space by clouds, some is absorbed by the atmosphere, and some is absorbed at the Earth's surface.
In this way, the Earth maintains a stable average temperature and therefore a stable climate (although of course differences in climate exist at different locations around the world).
Observed: 288 K = +15 C !
the amplitude of the diurnal
variation in surface T over land
greenhouse effect is very important
For nearly a billion years, ozone molecules in the atmosphere have protected life on Earth from the effects of ultraviolet rays
The ozone layer resides in the stratosphere and surrounds the entire Earth. UV-B radiation (280- to 315- nanometer (nm) wavelength) from the Sun is partially absorbed in this layer. As a result, the amount of UV-B reaching Earth’s surface is greatly reduced. UV-A (315- to 400-nm wavelength) and other solar radiation are not strongly absorbed by the ozone layer. Human exposure to UV-B increases the risk of skin cancer, cataracts, and a suppressed immune system. UV-B exposure can also damage terrestrial plant life, single cell organisms, and aquatic ecosystems.
In the past 60 years or so human activity has contributed to the deterioration of the ozone layer.
The retreat of glaciers since 1850, worldwide and rapid, affects the availability of fresh water for irrigation and domestic use, mountain recreation, animals and plants that depend on glacier-melting, and in the longer term, the level of the oceans. Studied by glaciologists, the temporal coincidence of glacier retreat with the measured increase of atmospheric greenhouse gases is often cited as an evidentiary underpinning of anthropogenic (human-caused) global warming. Mid-latitude mountain ranges such as the Himalayas, Alps, Rock Mountains, Cascade Range, and the southern Andes, as well as isolated tropical summits such as Mount Kilimanjaro in Africa, are showing some of the largest proportionate glacial loss
They are small tornadoes that develop on land. Though usually weaker than classic tornadoes, they still produce strong winds and may cause serious damage.
They are simply defined as small tornadoes over water, less intense and severe but far more common. They have relatively weak winds and they typically travel very slowly.
- dynamic processes on Earth,
- external forces (variations in sunlight intensity),
- and more recently by human activities.
Glaciers are recognized as being among the most sensitive indicators of climate change, advancing substantially during climate cooling (e.g., the Little Ice Age) and retreating during climate warming on moderate time scales. Glaciers grow and collapse, both contributing to natural variability and greatly amplifying externally forced changes. For the last century, however, glaciers have been unable to regenerate enough ice during the winters to make up for the ice lost during the summer months.
On the scale of decades, climate changes can also result from interaction of the atmosphere and oceans. Many climate fluctuations — including not only the El Niño Southern oscillation (the best known) but also the Pacific decadal oscillation, the North Atlantic oscillation, and the Arctic oscillation — owe their existence at least in part to different ways that heat can be stored in the oceans and move between different reservoirs.
On longer time scales ocean processes of circulation play a key role in redistributing heat, and can dramatically affect climate.
Current studies indicate that radiative forcing by greenhouse gases is the primary cause of global warming. Greenhouse gases are also important in understanding Earth's climate history. According to these studies, the greenhouse effect, which is the warming produced as greenhouse gases trap heat, plays a key role in regulating Earth's temperature.
During the modern era, the naturally rising carbon dioxide levels are implicated as the primary cause of global warming since 1950
Anthropogenic factors are human activities that change
the environment and influence climate.
Evidence for climatic change is taken from a variety of sources that can be used to reconstruct past climates.
Most of the evidence is indirect—climatic changes are inferred from changes in indicators that reflect climate, such as vegetation, ice cores, sea level change, and glacial retreat.
The 1980s and the 1990s have been the warmest since accurate and widespread instrumental records began, over a hundred years ago.
The year 1998 is very likely to have been the warmest year during this period.
Each of the first 8 months of 1998 was very likely the warmest of those months in the record.
The T record shows a considerable variability, not just from year to year, but from decade to decade. Although there is a distinct trend in it, the increase is not a uniform one.
The warming during the XXth century has not been uniform over the globe. For instance, the recent warming has been greatest over NH continents at mid to high latitudes. There have also been areas of cooling, for example over some parts of the North Atlantic ocean.
During the last few decades, in the daily cycle of T, minimum Ts over land have increased about twice as much as maximum T (possibly due not only to the effect of enhanced greenhouse gases but also to an increase in cloud cover).
T reconstruction over the last 1000 y from ‘’proxy’’ data (tree rings, corals, ice cores and historical records) calibrated against instrumental data
The increase in T has lead on average to increases in precipitation, although very variable in space and time
Significant cooling of the lower stratosphere has been observed over the last two decades.
This is to be expected both because of the decrease in concentration of ozone, which absorbs SW radiation, and because of the increased CO2 concentration, which leads to increased cooling at these levels.
We must in fact remember that the warming greenhouse effect can only operate in an atmosphere layer in which T decreases with height.
In the stratosphere, the thermal structure is characterized by T increasing with height and therefore more CO2 means cooling there.
Over the last hundred years, sea level has risen by 10-20 cm.
The best known contributions to this rise are from the thermal expansion of ocean water (estimated as up to 7 cm) and from glaciers which have generally been retreating over the last century (estimated as up to ~4 cm). The net contribution from the Greenland and Anctartica ice caps is more uncertain but is believed to be small.
Climate extremes (floods, droughts, tropical cyclones, windstorms etc…) have occurred frequently and with high severity during the last decades.
The Kyoto Protocol is a protocol to the United Nations Framework Convention on Climate Change (UNFCCC or FCCC), an international environmental treaty produced at the United Nations Conference on Environment and Development (UNCED), informally known as the Earth Summit, held in Rio de Janeiro, Brazil, from 3–14 June 1992.
The treaty is intended to achieve "stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system."
The Kyoto Protocol establishes legally binding commitments for the reduction of four greenhouse gases (carbon dioxide, methane,nitrous oxide, sulfur hexafluoride), and two groups of gases (hydrofluorocarbons and perfluorocarbons) produced by industrialized nations, as well as general commitments for all member countries. As of 2008, 183 parties have ratified the protocol, which was initially adopted for use on 11 December 1997 in Kyoto, Japan and which entered into force on 16 February 2005.
The objective is to achieve "stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system."
The treaty was negotiated in Kyoto, Japan in December 1997, opened for signature on 16 March 1998, and closed on 15 March 1999. The agreement came into force on 16 February 2005 following ratification by Russia on 18 November 2004. As of May 2008, a total of 181 countries and 1 regional economic integration organization (the EEC) have ratified the agreement.
Commitments. The heart of the Protocol lies in establishing commitments for the reduction of greenhouse gases that are legally binding for Annex I countries, as well as general commitments for all member countries
The five principal concepts of the Kyoto Protocol are:
Implementation. In order to meet the objectives of the Protocol, Annex I countries are required to prepare policies and measures for the reduction of greenhouse gases in their respective countries. In addition, they are required to increase the absorption of these gases and utilize all mechanisms available, such as joint implementation, the clean development mechanism and emissions trading, in order to be rewarded with credits that would allow more greenhouse gas emissions at home.
Minimizing Impacts on Developing Countries by establishing an adaptation fund for climate change.
Accounting, Reporting and Review in order to ensure the integrity of the Protocol.
Compliance. Establishing a Compliance Committee to enforce compliance with the commitments under the Protocol.
The United Nations Framework Convention on Climate Change agreed to a set of a "common but differentiated responsibilities." The parties agreed that:
The largest share of historical and current global emissions of greenhouse gases has originated in developed countries;
Per capita emissions in developing countries are still relatively low, and the share of global emissions originating in developing countries will grow to meet their social and development needs.
In other words, China, India, and other developing countries were not included in any numerical limitation of the Kyoto Protocol because they were not the main contributors to the greenhouse gas emissions during the pre-treaty industrialization period. However, even without the commitment to reduce according to the Kyoto target, developing countries do share the common responsibility that all countries have in reducing emissions.
There will be a mechanism of "compliance", which means a "monitoring compliance with the commitments and penalties for non compliance."
1) Some public policy experts who are sceptical of human-caused global warming see Kyoto as a scheme to either slow the growth of the world's industrial democracies or to transfer wealth to the third world in what these experts claim is a global socialism initiative.
2) Others argue the protocol does not go far enough to curb greenhouse emissions.
3) Some environmental economists have been critical of the Kyoto Protocol. Many see the costs of the Kyoto Protocol as outweighing the benefits, some believing the standards which Kyoto sets to be too optimistic, others seeing a highly inequitable and inefficient agreement which would do little to curb greenhouse gas emissions. Finally, some economists think that an entirely different approach needs to be followed than the approach suggested by the Kyoto-protocol.
4) Further, there is controversy surrounding the use of 1990 as a base year, as well as not using per capita emissions as a basis. Countries had different achievements in energy efficiency in 1990
Below is a list of the change in greenhouse gas emissions from 1990 to 2004 for some countries that are part of the Climate Change Convention as reported by the United Nations.
Below is a table of the changes in CO2 emission of some countries.
What are the possible
Are we really doomed to a catastrophic future?
How can we cut global warming pollution?
What can I do to help fight global warming?