Question

1)Now, the issue of the effect of carbon dioxide (carbon) is one that is hotly debated. You will find scientific arguments that indicate things are actually worse than the science-based models predict. And, you will find arguments that indicate the opposite. Some of these may not be well supported by science and thus do not hold up under careful scientific scrutiny.

Indeed, there is some thought that even if we were to eliminate most people-induced carbon emissions promptly, Earth would continue to warm up. Most climate scientists adhere to the belief that the data clearly show that increases in Greenhouse Gases are strongly correlated with increasing Earth temperatures and, indeed, are an important cause of those increases.

On the other hand, you will find sites on the web that take a different approach and form a different conclusion. Here is an example of such a site:

http://www.forbes.com/sites/jamestaylor/2013/03/06/as-carbon-dioxide-levels-continue-to-rise- global-temperatures-are-not-following-suit/

Based on what you know, do you see any flaw in the presentation that the author of the Forbes article has made? If you were in a discussion with the author, and you did not buy his argument, what would you say to try to convince him that he was wrong? (50 words or so should be adequate). Or, if you happen to think that the author is right, then what might you say to a skeptic of the author to try to convince the skeptic that the author has it right. So, one response here – if the author has a flaw, what can you say about it, or if the author has it right, what can you say that supports that point of view. Supportable arguments either way will be acceptable here. __________________________________________________________________________________

2) Speculation about what killed the dinosaurs has been an interesting subject for many years. We know by various techniques that about 65,000,000 year ago there ceased to be dinosaurs; they went extinct. So, something happened and they were killed off. As mentioned in class it is believed that many other forms of life were killed off at the same time. For many years the belief was that large scale volcanic activity caused so much serious pollution to the atmosphere that Earth cooled and plant life suffered and so did anything that depended on plants for survival, including dinosaurs.

But, this theory about volcanos lost some support when a curious discovery was made. Here is a site that talks about this interesting discovery, a discovery that resulted in what is known as the Alvarez Impact Hypothesis. Take a look at this next site and respond to the questions below.

[This web site was updated in April 2019 to include a rather remarkable new discovery, which we will engage further below.]

http://en.wikipedia.org/wiki/Alvarez_hypothesis

What did Alvarez and a small team actually discover? (25 words should be enough) Note: This does not ask what he proposed, but asks what he actually found in his field work? _______________________________

3) So, did a meteor impact kill the dinosaurs, or was something more gradual also involved, like climate change due to, for example, volcanoes? Here is a 2013 article from National Geographic that offers some new insight.

http://news.nationalgeographic.com/news/2013/13/130212--chicxulub-asteroid-dinosaurs- volcano-mass-extinction-environment-science/

What is the bottom line of the Geographic article? Was it the asteroid, was it volcanoes, or what was it, or do we really know yet? (25 words should be enough). _________________________

4) Very recently there was published a remarkable discovery, one that claims to have found clear evidence for the catastrophic damage that the Alvarez Impact event caused, and claims that the evidence recently found was created on the same day that the impact took place. A rather lengthy, but very readable account of this was published in the 8 April, 2019 issue of the New Yorker magazine. The first of a sequence of scientific articles has been published in the scientific journal Proceedings of the National Academy of Sciences. A quite accessible and not too lengthy account of this discovery is available at this web site:

https://www.pbs.org/wgbh/nova/article/new-fossils-mass-extinction-wiped-out-dinosaurs/

Take a look at the article on the PBS link and respond to these questions:

What is the name given to a glassy bead formed from molten bedrock?  _____________________________

What makes the lead investigator (Robert DePalma) rather certain that his discovery is a discovery of a site that captures events that happened on the very day that the asteroid struck Earth? (about 50 words will do). _______________________________________________

Answer 1

1) What we really need to understand here is that Climate in other words can mean variation as it has many variables which are constantly changing since the time climate tracking has been done and one variable might trigger a change in other which can affect both positively as well as negatively and the overall effect is what decides the habitability of the planet.In the past years Climate Change has gained so much importance because there are serious changes that the world is facing and these changes are a cause of concern because humans have contributed in causing these changes and their actions have become one of the variables and that is the real problem because the overall impact has been damaging and proves that is a need to take measures to minimise the harmful effects.

2) Alvarez and his team found that the Isotopic Iridium ratio in meteorites was similar to that found in Cretaceous-Paleogene boundary layer and this ratio was very different from that found in earths crust.Apart from this the isotopic ratio of chromium also showed a similar trend all of this hinting towards the Asteroid collision which wiped out the vast population of Dinosaurs at once.

3) The article states that although Asteroid collision was the major cause of mass extinction of these dinosaurs volcanic eruption is also partly a reason which helped in wiping out the whole population of dinosaurs.