B.How have human activities contributed to the phenomenon known as global warming?

Answer 1

Projected climate changes due to global warming have the potential to lead to future large-scale and possibly irreversible changes in our climate resulting in impacts at continental and global scales.

Examples of projected climate changes include:

significant slowing of the ocean circulation that transports warm water to the North Atlantic,
large reductions in the Greenland and West Antarctic Ice Sheets,
accelerated global warming due to carbon cycle feedbacks in the terrestrial biosphere, and
releases of terrestrial carbon from permafrost regions and methane from hydrates in coastal sediments.
The likelihood of many of these changes is uncertain. However, the probability of one or more of these changes occurring is likely to increase with the rate, magnitude, and duration of climate change.

The effects of global warming are not uniformly negative. Global warming will lead to climate change which will have positive benefits in some regions and negative effects in others. Scientists are unable to accurately predict when various effects of global warming will occur or what the magnitude of the effect will be.

For this reason, it is not possible to be certain whether the positive benefits will outweigh the negative impacts. What is known is that some significant negative impacts are projected and these drive most of the concern about global warming and motivates attempts to mitigate or adapt to the effects of global warming.

Most of the consequences of global warming would result from one of three physical changes: sea level rise, higher local temperatures, and changes in rainfall patterns .Sea level is generally expected to rise 50-200 cm in the next century (Dean et al. 1987); such a rise would inundate 7,000 square miles of dry land in the United States (an area the size of Massachusetts) and a similar amount of coastal wetlands; erode recreational beaches 100-200 meters, exacerbate coastal flooding; and increase the salinity of aquifers and estuaries (Titus 1989

Answer 2

Humans HAVE contributed to global warming through the production of carbon dioxide from burning fossil fuels. The evidence is very strong that the atmospheric level of CO2 has increased tremendously since we began burning huge amounts of coal and oil.

Answer 3

It has not been shown that human activities are of sufficiently large scale to influence global warming, but if they were, the generation of so-called "green house gases" such as carbon dioxide and methane would be contributing factors.

Answer 4

Here's an example. Al Gore wrote a book about global warming. Books are made from cutting down trees. He also flies around in jets promoting his book. Jets fly off of fossil fuel.

Answer 5

Global warming is a hoax.