Has our climate changed? How do scientists determine that?
Please click on the link "http://legonanites.blogspot.com/ " and respond with your answer by entering it as comment. You need to respond to each quiz before our next meeting.
Please click on the link "http://legonanites.blogspot.com/ " and respond with your answer by entering it as comment. You need to respond to each quiz before our next meeting.
Please note everyone on the Internet can see your answer.
Posts
2 comments:
Our climate has changed, with an approximate 0.7 Celsius increase globally. (I am still not sure how they measure this, though)Scientists can determine how the climate changed due to many different things, such as the retreat of glaciers and sea ice, a 40% decrease in the thickness of the Artic ice, an average of a 20 mm increase in sea level over the last 20 years, and an increase in cloral bleaching due to warmer water temperatures. Scientists also have found that at the moment, there is more carbon dioxide in the atmosphere than there has been in the past 420,000 years. They can determine this through ice core drilling.
Since 1910 the Earth has warmed about 33 degrees Fahrenheit. Nine of the ten hottest years in record have been in the past decade. There have also beenmore heatwaves and less frosts. The lower atmoshpere and upper ocean have heated up.
Tempature records from about 250 years ago show a genral rise upward. Unfourtunetly, actual records of tempature were scrace before the 1700's. Luckily for scientists nature has made its own tempature recordings for a very long time. One way is how trees grow faster in warmer weather and slowere in colder weather. Scientists can figure out when it was cooler by looking at the growth rings of different species. ANother way to tell the tempature from a long time ago is to use little creatures called forams. The creatures take oxegen out of the salty seawaster and then combine it with carbon and calcium. This procces helps them make their shells. Even though we all think that oxegen is the same there are several different s types or isotopes. Nomrmal oxegen is called oxegen 16.There is also an isotopes that is heavier called oxegen 18. More oxegen 18 in the ocean means that there is more glacier ice in the world which would mean a colder climate. By comparing the ratios of oxegen 16 and oxegen 18 in the shells of sea creatures who lived long ago, scientists can detirmine the climate of the past.
Post a Comment