global cycling of carbon
The image below shows a simplified carbon cycle.
You can read about the carbon cycle in detail here.
relevance to the issue of global warming
Carbon exists in various forms, one of which is carbon dioxide. The relationship between carbon dioxide and global warming is explained fully here.
Carbon also exists as methane, which is another greenhouse gas contributing to climate change.
Forests are typically carbon sinks, meaning they store carbon. When they are removed, they release carbon into the atmosphere. Thus, deforestation contributes to increased amounts of carbon in the atmosphere and increased warming.
There is also the potential for feedback effects. For example, as the planet warms, the rate of decomposition will increase soils will release more carbon dioxide into the atmosphere.
To conclude, the carbon cycle and global warming are intimately connected, and a change in one portion of the carbon cycle leads to changes elsewhere. Burning fossil fuels removes carbon from the soil and releases it into the atmosphere. Removing trees, which take in carbon dioxide during photosynthesis, releases more carbon dioxide into the atmosphere. These disruptions and others to the carbon cycle are key drivers of global warming and anthropogenic climate change.
El Niño is the warming phase where sea surface temperatures are warmer in the central-eastern Pacific. In South America, warmer and wetter months occur during an El Niño. California also experiences increased rainfall during El Niño. Australia and Southeast Asia are drier than normal.
La Niña is the cold phase where cooler ocean temperatures are found in the central-eastern Pacific. In Southeastern Asia, La Niña causes heavy rains. Ecuador and Peru, which were wet during El Niño, are dry. The midwestern US experiences drier summers and wetter winters during La Niña.
You can read more about ENSO and precipitation here.
Biomass, geothermal, wind, tidal, solar, and hydroelectric
Biomass energy : The dilemma is "Food for people or food for energy?". It is good if a country can provide land for biomass production and does not encounter food deficiency.
Geothermal energy: In some areas the geothermal gradient is sufficient enough to exploit to generate electricity. Disadvantage of it is that geothermal liquids contain many different types of minerals and elements. When they are allowed to flow free, they might pollute the environment (for example in Aydin Buharkent Turkey).
Wind energy: When wind is in sufficient velocity, people want to benefit from it by using wind turbines. The disadvantages of it can be listed as: some birds and bats as well as bees die when this turbines are operated, a certain amount of land (a quarter US acre for example) is necessary to erect wind turbines (wind power company has to cut down trees and clear the area), noise pollution, etc.
Tidal power : During high-tide event store sea water and then when it is low-tide people can produce electric by operating specific turbines. The disadvantages of it are that not everywhere you can see this activity, some fish species might be affected, you disturb some coastal areas, etc.
Solar power: PV technology depends on sunshine. Under sunny conditions, mild (in terms of wind) conditions and less dusty (particulate matter) circumstances, photovoltaics can provide electricity. You need free land to build PV arrays. Some people argue that some birds and other avians are negatively affected by such structures.
Hydroelectric (dams): Water is cycled in nature. When you build a dam on suitable places on a river, you can store water and produce electricity by operating turbines. There are some disadvantages of such structures. First, stagnant water bodies do not oxygenate (aerate) easily compared to that in streams (rivers). Therefore, they are delicate to pollution. Moreover, some migrating fish species could not move towards upstream. They are badly affected. Finally, such large dams slow down the rotational velocity of the earth.
There are many issues related to renewable energy indeed. I was warned that I have provided a long answer. So far, that is it.
The process of photosynthesis removes Carbon dioxide from the atmosphere and turns the Carbon into Carbohydrates such as sugar starches, and cellulose.
The process of photosynthesis uses Carbon Dioxide as a reactant removing the Carbon Dioxide from the atmosphere. The reduction of Carbon Dioxide from the atmosphere helps to reduce global warming.
During the Mesozoic Era there were high levels of Carbon Dioxide that resulted in high levels of photosynthesis. The era of high carbon dioxide is also known as the Carboniferous Era. The High levels of Carbon Dioxide created large amounts of plant growth that created the coal deposits.
High levels of photosynthesis take large amounts of Carbon Dioxide out of the atmosphere to create sugars and starches used for plant growth.
One example is volcanic explosions.
When Krakatoa exploded in 1883 the entire world experienced a number of years of unusually cold weather, due to the volcanic dust in the atmosphere. The average temperature in England dropped more than 2 degrees. Temperatures did not return to normal until 1888.
Another volcanic explosion in Indonsia of Mount Tambora in 1815 resulted in the year with no summer. The amount of volcanic dust blocked the sun's rays from reaching and warming the earth. The summer after the explosion was cold throughout the world.
One theory is that the dinosaurs died because of increased volcanic activity due to unusually rapid movement of the tectonic plates. The high volcanic activity created a colder climate than the large cold blooded dinosaurs could quickly adapt to.
Volcanic activity can quickly change the climate of the world.
Animal agriculture has a significant and negative impact on the environment.
Animal agriculture has a significant and negative impact on the environment. The main impacts fall are 1. animal agriculture uses a lot of land, 2. greenhouse gas emissions from animal agriculture are higher than most realize and 3. the animal agriculture industry uses a lot of water.
Methane is released when cows and other ruminants burp, and this GHG lasts much longer in the atmosphere than carbon dioxide. The GHG emissions tied to animal agriculture is also related to the amount of land used in this industry. Whenever land is converted from forests, which are carbon dioxide sinks, this process of removing the GHG from the atmosphere is replaced with less biomass and therefore a less effective CO2 removal method.
Water is needed for the animals themselves but it is also needed to grow all of their feed. Beef has a particularly large impact: it takes 15,415 liters of water per kilogram of beef. If you look at the impact of a human and a dairy cow at the end of both of their lifespans, the dairy cow has a larger impact on water despite a much shorter lifespan (source)
Animal agriculture also has many of the problems agriculture has, and you can read about those here.
Yes plants undergo adaptive evolution just like animals.
The evolution or change in organisms can be observed in nature.
The existing genetic variation provides natural selection with the material needed for changes in the population.
In the desert, plants that have glossier leaves will be better adapted to the dry conditions in the desert environment. As the climate changes the varieties of the plant with less glossy leaves were unable to survive and reproduce as well as plants with more glossy leaves. This will create a change in the population. This is an example of adaptive evolution.
A classic example in animal adaptive evolution is the peppered moth in England. Before the Industrial Revolution the peppered moth population was primarily white with a small minority of black moths. During the Industrial Revolution and the extensive use of coal the black variety was better adapted to the changing environment. After the use of coal sharply declined with the use of electric power, the white variety again was better adapted. The population went from mainly white, to mainly black, to back to mainly white.
Natural selection can only select from existing variations, Presently observed changes in the existing variations are all results of a loss of genetic information. Examples such as bacterial resistance , (see the Beak of the Finch page 260), resistance to malaria, and the blind fish of Death Valley are all due to the loss of genetic information.
Both animals and plants are subject to adaptive evolution and genetic changes due to loss of genetic information. Note Darwinian evolution is an unobserved extrapolation of the observed adaptive evolution.
Crop rotation, contour farming, terracing, and shelter belt.
Crop rotation is a huge benefit when fighting against soil degradation. Annually or so, the crop on one patch of land is rotated, so one year is wheat, the next soybeans, etc. The diversity of plants help to maintain soil quality.
Contour farming is also a great way to battle soil degradation. This is pretty much plowing ridges in the soil to prevent run-off of water and nutrients, etc to minimize soil erosion.
Terracing is most commonly seen in rice fields. And since rice needs lots of water, terracing, or forming of stair-like steps will minimize the water loss in fields, and will maintain soil and prevent erosion.
Finally, the shelter belt is also a great way to maintain soil health. In fields, trees are planted in a line or a belt, to block the wind to prevent top soil being blown away.
Bacteria helps the nitrogen cycle along throughout many of the processes.
In the nitrogen fixation process, nitrogen fixing bacteria converts the
During assimilation, or when plants take up nitrates from the soil, bacteria aid in the process with the plants in making ammonia. Animal wastes is also a major place where bacteria thrives and produces ammonia. The process in which assimilation occurs in plants, and then bacteria converts the nitrates to ammonia is called ammonification.
From the conversion of ammonia to nitrites, bacteria also aids in this process called nitrification. The nitrifying bacteria mostly present in soils, oxidize ammonia into nitrites, and from nitrites to nitrates.
Finally, the process of denitrification also has bacteria present to aid in converting nitrates back into a gaseous form of nitrogen in the atmosphere.
In a nutshell, bacteria aids in the nitrogen process through nitrogen fixation, assimilation, nitrification, and finally denitrification.
An indicator species is an organism whose presence, absence or abundance reflects a specific environmental condition.
Indicator species are an appealing research and monitoring tool.
Indicator species can signal a change in the biological condition of a particular ecosystem, and thus may be used as a proxy to diagnose the health of an ecosystem.
For example, plants or lichens sensitive to heavy metals or acids in precipitation may be indicators of air pollution.
Indicator species can also reflect a unique set of environmental qualities or characteristics found in a specific place, such as a unique microclimate. However, care must be exercised in using indicator species.
Indicator species are sometimes called proxy or surrogate species.