Global warming help? 10 points?

Question

i just need help with some of the causes and effects of things related to greenhouse gases

so if you know any of the answers please help me

thanks a lot

1. cause ?

effect: glaciers have been retreating since the 1800's

2. cause: melting glaciers will decrease the ocean's salinity

effect ?

3. cause: deep ocean currents are driven by highlysaline water of the North Atlantic. Heavy saltwater sinking to the ocean bottom in the north cause warm waters to flow northward.

effect: ?

Answer 1

1. The cause of glacier retreating since the 1800's was ever since the beginning of the industrial revolution. Which was burning of fossil fuels, coal, oil, etc. It has released Carbon Dioxide and Methane. It has resulted in more absorption of solar radiation by the atmoshope which has caused more warmer temperatures.

2. If the glaciers melt, it has been hypothesized by scientists that glacier melt water will may cause shut down of the gulf streams currents and it can result in the climate of Northern Europe more closely, resembling that of Labrador the difference of salinity between the warm surface current and the cold, deep return current amounts to only parts per thousand of salt.

3. This is an accurate description of the Gulf Stream current. It's effects are a milder climate in northern Europe and in the British Isles.

Answer 2

1.  

Causes of Glacial Ages

In order to understand what causes these cycles of glacial - interglacial episodes we need a much better understanding of what causes global climate changes. Because human history is so short compared to the time scales on which global climate change occurs, we do not completely understand the causes. However, we can suggest a few reasons why climates fluctuate.

Long term variations in climate (tens of millions of years) on a single continent are likely caused by drifting continents. If a continent drifts toward the equator, the climate will become warmer. If the continent drifts toward the poles, glaciations can occur on that continent.

Short-term variations in climate are likely controlled by the amount of solar radiation reaching the Earth. Among these are astronomical factors and atmospheric factors.

Astronomical Factors -

Variation in the eccentricity of the Earth's orbit around the sun has periods of about 400,0000 years and 100,000 years.

Variation in the tilt of the Earth's axis has a period of about 41,000 years.

Variation in the way the Earth wobbles on its axis, called precession, has a period of about 23,000 years.

The combined effects of these astronomical variations results in periodicities similar to those observed for glacial - interglacial cycles.

Atmospheric Factors- the composition of the Earth's atmosphere can be gleaned from air bubbles trapped in ice in the polar ice sheets. Studying drill core samples of such glacial ice and their contained air bubbles reveals the following:

During past glaciations, the amount of CO2 and methane, both greenhouse gasses that tend to cause global warming, were lower than during interglacial episodes.







During past glaciations, the amount of dust in the atmosphere was higher than during interglacial periods, thus more heat was likely reflected from the Earth's atmosphere back into space.

The problem in unraveling what this means comes from not being able to understand if low greenhouse gas concentration and high dust content in the atmosphere caused the ice ages or if these conditions were caused by the ice ages.

  

Changes in Oceanic Circulation - small changes in ocean circulation can amplify small changes in temperature variation produced by astronomical factors.

Other factors:

The energy output from the sun may fluctuate.

Large explosive volcanic eruptions can add significant quantities of dust to the atmosphere reflecting solar radiation and resulting in global cooling.



2. Melting sea ice would tend to reduce ocean stratification because the seasonal cycle of freezing and melting of sea ice tends to strengthen vertical salinity and density gradients in the present-day ocean. This occurs because ice formation tends to cause sinking of saltywater, whereas melting ice freshens the surface ocean. The net effect is to make the surface fresher, and the subsurface ocean saltier. This therefore tends to increase density stratification; coupled with more air–sea gas exchange due to reduced sea ice cover, it tends to produce faster uptake of anthropogenic CO2 .

3. When the strength of the haline forcing increases due to excess precipitation, runoff, or ice melt the conveyor belt will weaken or even shut down. The variability in the strength of the conveyor belt will lead to climate change in Europe and it could also influence in other areas of the global ocean. The North Atlantic atmosphere-ocean-cryosphere system appears to have natural cycles of many timescales in switching the conveyor belt. Periodic movement of excessive ice from the Arctic into the Greenland Sea appears to be responsible for the interdecadal variability of the conveyor belt. There is no evidence yet that the influx of interdecadal switching extends beyond the North Atlantic Ocean. .