Wednesday, May 14, 2008
Monday, May 12, 2008
What about the future of The Earth?
What about the future?
Due to the enormous complexity of the atmosphere, the most useful tools for gauging future changes are 'climate models'. These are computer-based mathematical models which simulate, in three dimensions, the climate's behavior, its components and their interactions. Climate models are constantly improving based on both our understanding and the increase in computer power, though by definition, a computer model is a simplification and simulation of reality, meaning that it is an approximation of the climate system. The first step in any modeled projection of climate change is to first simulate the present climate and compare it to observations. If the model is considered to do a good job at representing modern climate, then certain parameters can be changed, such as the concentration of greenhouse gases, which helps us understand how the climate would change in response. Projections of future climate change therefore depend on how well the computer climate model simulates the climate and on our understanding of how forcing functions will change in the future.
The IPCC Special Report on Emission Scenarios determines the range of future possible greenhouse gas concentrations (and other forcings) based on considerations such as population growth, economic growth, energy efficiency and a host of other factors. This leads a wide range of possible forcing scenarios, and consequently a wide range of possible future climates.
According to the range of possible forcing scenarios, and taking into account uncertainty in climate model performance, the IPCC projects a best estimate of global temperature increase of 1.8 - 4.0°C with a possible range of 1.1 - 6.4°C by 2100, depending on which emissions scenario is used. However, this global average will integrate widely varying regional responses, such as the likelihood that land areas will warm much faster than ocean temperatures, particularly those land areas in northern high latitudes (and mostly in the cold season). Additionally, it is very likely that heat waves and other hot extremes will increase.
Precipitation is also expected to increase over the 21st century, particularly at northern mid-high latitudes, though the trends may be more variable in the tropics, with much of the increase coming in more frequent heavy rainfall events. However, over mid-continental areas summer-drying is expected due to increased evaporation with increased temperatures, resulting in an increased tendency for drought in those regions.
Snow extent and sea-ice are also projected to decrease further in the northern hemisphere, and glaciers and ice-caps are expected to continue to retreat.
(Thanks : http://lwf.ncdc.noaa.gov/oa/climate/globalwarming.html#q11)
Due to the enormous complexity of the atmosphere, the most useful tools for gauging future changes are 'climate models'. These are computer-based mathematical models which simulate, in three dimensions, the climate's behavior, its components and their interactions. Climate models are constantly improving based on both our understanding and the increase in computer power, though by definition, a computer model is a simplification and simulation of reality, meaning that it is an approximation of the climate system. The first step in any modeled projection of climate change is to first simulate the present climate and compare it to observations. If the model is considered to do a good job at representing modern climate, then certain parameters can be changed, such as the concentration of greenhouse gases, which helps us understand how the climate would change in response. Projections of future climate change therefore depend on how well the computer climate model simulates the climate and on our understanding of how forcing functions will change in the future.
The IPCC Special Report on Emission Scenarios determines the range of future possible greenhouse gas concentrations (and other forcings) based on considerations such as population growth, economic growth, energy efficiency and a host of other factors. This leads a wide range of possible forcing scenarios, and consequently a wide range of possible future climates.
According to the range of possible forcing scenarios, and taking into account uncertainty in climate model performance, the IPCC projects a best estimate of global temperature increase of 1.8 - 4.0°C with a possible range of 1.1 - 6.4°C by 2100, depending on which emissions scenario is used. However, this global average will integrate widely varying regional responses, such as the likelihood that land areas will warm much faster than ocean temperatures, particularly those land areas in northern high latitudes (and mostly in the cold season). Additionally, it is very likely that heat waves and other hot extremes will increase.
Precipitation is also expected to increase over the 21st century, particularly at northern mid-high latitudes, though the trends may be more variable in the tropics, with much of the increase coming in more frequent heavy rainfall events. However, over mid-continental areas summer-drying is expected due to increased evaporation with increased temperatures, resulting in an increased tendency for drought in those regions.
Snow extent and sea-ice are also projected to decrease further in the northern hemisphere, and glaciers and ice-caps are expected to continue to retreat.
(Thanks : http://lwf.ncdc.noaa.gov/oa/climate/globalwarming.html#q11)
Sunday, May 11, 2008
How to Deep Water Plants
- Step1 Use a soaker hose around the drip line of existing landscape trees. Turn on the water to a very slow flow and allow it to run as long as overnight. Roots grow where the soil is damp. By driving the water deep into the soil, you encourage roots to follow.
- Step2 Purchase a deep watering tool that can be attached to the end of a hose. Turn on the water 1/4 strength - any stronger will wash the soil away from the roots. Plunge the spike end into the soil around the drip line of existing landscape shrubs. Move around the tree, watering in 8-10 places around the drip line.
- Step3 Wrap the end of a hose with an old cotton sock. Use a rubber band to hold it in place. Turn on the water to a slow trickle and place the sock end of the hose near the drip line. Allow the water to run for several hours, then move the hose 1/4 revolution around the drip line. Continue until the entire perimeter of the tree has been watered. The sock breaks the force flow of the water so that it doesn't wash the soil away.
- Step4 Set up permanent soaker hoses under redwood trees and cover with mulch. Although redwoods are shallow rooted and don't require deep watering, their wide, flat mat of roots will benefit from a biweekly application of water applied directly to the roots during the summer and fall. Allow the water to run for several hours at a very slow volume.
- Step5 For flowering summer annuals, such as marigolds, form an earthen bowl around the plant and fill it with water, allowing the water to soak into the earth. Do this once a week to encourage deep root growth and larger, stronger plants.
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