Temperature changes

The most commonly discussed measure of global warming is the trend in globally averaged temperature near the Earth's surface. Expressed as a linear trend, this temperature rose by 0.74°C ±0.18°C over the period 1906-2005. The rate of warming over the last 50 years of that period was almost double that for the period as a whole (0.13°C ±0.03°C per decade, versus 0.07°C ± 0.02°C per decade). The urban heat island effect is estimated to account for about 0.002 °C of warming per decade since 1900.[8] Temperatures in the lower troposphere have increased between 0.12 and 0.22 °C (0.22 and 0.4 °F) per decade since 1979, according to satellite temperature measurements. Temperature is believed to have been relatively stable over the one or two thousand years before 1850, with regionally-varying fluctuations such as the Medieval Warm Period or the Little Ice Age.
Based on estimates by NASA's Goddard Institute for Space Studies, 2005 was the warmest year since reliable, widespread instrumental measurements became available in the late 1800s, exceeding the previous record set in 1998 by a few hundredths of a degree.[9] Estimates prepared by the World Meteorological Organization and the Climatic Research Unit concluded that 2005 was the second warmest year, behind 1998.[10][11] Temperatures in 1998 were unusually warm because the strongest El Niño in the past century occurred during that year.[12]
Temperature changes vary over the globe. Since 1979, land temperatures have increased about twice as fast as ocean temperatures (0.25 °C per decade against 0.13 °C per decade).[13] Ocean temperatures increase more slowly than land temperatures because of the larger effective heat capacity of the oceans and because the ocean loses more heat by evaporation.[14] The Northern Hemisphere warms faster than the Southern Hemisphere because it has more land and because it has extensive areas of seasonal snow and sea-ice cover subject to the ice-albedo feedback. Although more greenhouse gases are emitted in the Northern than Southern Hemisphere this does not contribute to the difference in warming because the major greenhouse gases persist long enough to mix between hemispheres.[15]
The thermal inertia of the oceans and slow responses of other indirect effects mean that climate can take centuries or longer to adjust to changes in forcing. Climate commitment studies indicate that even if greenhouse gases were stabilized at 2000 levels, a further warming of about 0.5 °C (0.9 °F) would still occur.[16]

What is GLOBAL WARMING?

Global warming is the increase in the average temperature of the Earth's near-surface air and oceans since the mid-20th century and its projected continuation. Global surface temperature increased 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the last century.[1][A] The Intergovernmental Panel on Climate Change (IPCC) concludes that increasing greenhouse gas concentrations resulting from human activity such as fossil fuel burning and deforestation caused most of the observed temperature increase since the middle of the 20th century.[1] The IPCC also concludes that variations in natural phenomena such as solar radiation and volcanoes produced most of the warming from pre-industrial times to 1950 and had a small cooling effect afterward.[2][3] These basic conclusions have been endorsed by more than 40 scientific societies and academies of science,[B] including all of the national academies of science of the major industrialized countries.[4] A small number of scientists dispute the consensus view.
Climate model projections summarized in the latest IPCC report indicate that the global surface temperature will probably rise a further 1.1 to 6.4 °C (2.0 to 11.5 °F) during the twenty-first century.[1] The uncertainty in this estimate arises from the use of models with differing sensitivity to greenhouse gas concentrations and the use of differing estimates of future greenhouse gas emissions. Some other uncertainties include how warming and related changes will vary from region to region around the globe. Most studies focus on the period up to the year 2100. However, warming is expected to continue beyond 2100 even if emissions stop, because of the large heat capacity of the oceans and the long lifetime of carbon dioxide in the atmosphere.[5][6]
An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, probably including expansion of subtropical deserts.[7] The continuing retreat of glaciers, permafrost and sea ice is expected, with warming being strongest in the Arctic. Other likely effects include increases in the intensity of extreme weather events, species extinctions, and changes in agricultural yields.
Political and public debate continues regarding climate change, and what actions (if any) to take in response. The available options are mitigation to reduce further emissions; adaptation to reduce the damage caused by warming; and, more speculatively, geoengineering to reverse global warming. Most national governments have signed and ratified the Kyoto Protocol aimed at reducing greenhouse gas emissions.

Global Warming

Global warming may or may not be a problem. Man may or may not be driving it. Given the uncertainties, a significant amount of global regret may apply if we divert too much of our global wealth to solving what may be a non-existent or trivial problem, especially if that diversion mires billions in poverty. On the other hand, we may also regret not doing anything if man-made global warming does turn out to be a problem. It is therefore prudent to examine what steps we can take that would prove beneficial whether or not anthropogenic global warming turns out to be a problem. These steps can be termed “no regrets” policies.
What makes a No Regrets Global Warming Policy? A global warming policy can be termed “no regrets” as long as it:
Reduces the amount of greenhouse gases emitted into the atmosphere, or
Mitigates, prevents or reduces a harm associated with global warming, or
Provides greater capacity for dealing with problems associated with global warming
Without imposing significant cost or diverting economic activity.
Top Five “No Regrets” Policies
1.) Eliminate all subsidies to fuel use.Subsidies to energy R&D cost taxpayers millions of dollars while producing minimal benefits. While these programs may be relatively small given the size of domestic energy markets, they serve little, if any, useful purpose while subsidizing large corporations at taxpayer expense. The potential threat of global warming, whether it is real or not, is simply one more reason to eliminate these subsidy programs. An international agreement aimed at ending energy subsidy with binding targets would be a significant victory for emissions reduction. Unlike Kyoto, which forces an energy starvation diet on its participants, such a treaty would be a move to combat energy obesity.
2.) Repeal the Federal Flood Insurance Program.Much of the concern over global warming’s potential for harm in the US relates to sea level rise and the flooding that will result. However, much of the investment in potentially vulnerable areas is a result of the Federal flood Insurance Program. This program encourages building in vulnerable areas by acting as a moral hazard: people take greater risks because the government has said it will help bear that risk. Reform would reduce the moral hazard connected with building on vulnerable land, transferring the risk from the taxpayer to the private sector, which is likely to take a more realistic view of the issue.
3.) Reform Air Traffic Control Systems.Greater demand for air travel means more flights, which means greater fuel use and increased emissions. Yet, the current government-operated system of air traffic control, based on a 1920s-era system of beacons, may hinder innovations that could reduce fuel use and emissions. As a general rule, the shorter the flight, the less fuel will be consumed. Yet neither airlines nor pilots have the freedom to choose the most direct and economical route. Giving pilots freedom to map their own course is an attractive and desirable change in the eyes of the industry, and the impact on the environment would be tremendous. As well as saving considerable amounts of greenhouse gas emissions, the policy will deliver significant benefits in terms of time and expense to the US economy. By obviating significant reductions in service levels associated with more routine applications of emissions reduction policy, it is to be preferred to that approach.
4.) Facilitate Electricity Competition.By rejecting the model of central regulation and allowing suppliers to meet their customers’ needs more exactly while relying on distributed generation, energy waste and the associated emissions will reduce considerably. This reduction in waste will prove economically beneficial even if emissions themselves do not cause problems.
5.) Reduce Regulatory Barriers to New Nuclear Build.There is no other technology than nuclear that is proven to be capable of providing emissions-free energy at the scale required to make significant reductions in carbon emissions. The problem is that thanks to anti-nuclear activism by environmentalists in the 1970s, it takes a very long time to build a nuclear plant. This pushes development and construction costs up to the level where it is not economically competitive with higher-emitting forms of electricity generation like coal and natural gas. According to the nuclear energy institute, it takes 10 years from concept to operation to build a nuclear plant, and only four of those are construction, the rest is permit application development (2 years) and decision-making by the Nuclear Regulatory Commission (4 years).