We keep hearing that the climate is changing, but we are not very exposed to the evidence that support this. We are aware that the Earth is warming, however it is not warming uniformly all over the planet, and some regions have experienced more warming than others. Generally, land areas have warmed more than the oceans. I have outlined below some of the evidence that supports this statement.
- Satellite Measurements of Temperature: Global temperature can be measured via orbit and the US have been flying satellites since 1978. However, possibilities of error have been explored with this type of measurement. One area of potential error is that satellites do not measure surface temperature, rather they measure the temperature of the bottom 8 km of the atmosphere. Another possible area of error with satellite measurement is orbit drift.
- Ice: The lengths of glaciers all over the world have been measured and show a clear pattern in the receding of these glaciers. The fact that this retreat of glaciers is happening in places all over the world means that the cause is global. It provide confirmation that global warming is occurring. Measurements of sea ice also confirm that is decreasing in thickness. This is further confirmation of the warming of the climate on a global level.
Ice sheet melting in Greenland
- Ocean Temperatures: Oceans are observed to be warming as well over time. This is because the heat trapped by greenhouse gases goes into the oceans.
- Sea Level: As grounded ice melts, the melted water runs to the ocean and increases the amount of water, thereby increasing the sea level. Another concern with the increase in sea level is that when water is warmed, it expands. This expansion of water further causes a rise in sea level.
There you have it folks,all the evidence out on the table. The Earth’s climate is changing. The above stated data are susceptible to errors therefore several types of confirmations are needed to make sure that there is no flaw in the research.
Below are two other articles that have been published by James Hansen on the topic.
http://www.atmos.washington.edu/~davidc/ATMS211/articles_optional/Hansen81_CO2_Impact.pdf
http://www.nature.com.ezproxy.library.ubc.ca/scientificamerican/journal/v290/n3/full/scientificamerican0304-68.html
