Bradley: Natural Archives, changing climates

Overall I believe that the lecture was interesting and intense. If I could ask him any two questions it would be these:

1.  What about the places that do not have ice there? How do we help determine the climate in those areas?

2.  Where are the places that hold the oldest ice?

Both of these questions I feel would be interesting to have answered by Ray Bradley. I would like to know these answers because they personally interest me when it comes climate change and paleoclimatology.

What Caused the Ice Ages?

In order for the Ice Ages to occur, it was not just a simple cause and effect. There are four things that have to occur before an Ice Age begins. The first thing that needs to be set up would be the boundary conditions. This means that the position of the continents would have to be further north, to allow an ice sheet to be formed. Also having tectonic plates collide, creating mountains, would emit less CO2 in the air. The second thing needed is the trigger, which has to do with the Earth's rotation around the Sun. With the boundary conditions pushing the Earth towards a tipping point, a small trigger like the Earth being just a little bit farther from the Sun can trigger dramatic changes. Feedbacks occur when the ice and snow cause the Earth's albedo to reflect more of the energy and absorb less. This causes the planet to get colder, pushing it to create more snow and continue the effect. The tipping point then occurs as the snow and ice begin to build up, the globe gets colder and glaciers begin to form. This is how the Ice Ages began.

The Figure above shows the variation that the Earth can have when orbiting the Sun. When Earth becomes too far away, it creates a great environment to host an Ice Age.

Source: here

Paleoclimatology

What is paleoclimatology? 
Paleoclimatology is the study of past climates. By determining what had happened in the past, scientist hope to understand better what the future may hold for us.

How is it studied? 
You can find different chemical and physical alterations around the world that show the previous climates and how the ocean land and air were affected. Some of the things studied are able to determine a characteristic that is world wide and others are for specific regions. "Proxy" records is the name of the things that scientists find in the environment. Proxy records are the records found in tree rings, in the skeletons of the coral reef, ice cores from glaciers and sediments buried in the ocean and land.

Why is it studied?
Studying this helps scientists reconstruct the past in order to help determine what may happen in the future or with human influence. It has already been previously shown using paleoclimatology that the Earth's climate can dramatically change within a matter of decades. Paleoclimatology also shows us the human influence that already exists on the Earth.

The Climate was Cooling? Wait what?

Yes, it is true. In the mid 20th century the globe was actually cooling due to aerosol emissions. The globe only cooled about 0.1 degrees Celsius, but this was a huge change in the trend of the 20th century. The aerosols had such an influence on the climate because it has direct and indirect effect. The aerosols were put in the atmosphere primarily from burning fossil fuels. The primary idea from reading this article and this article is that the cooling during this time was unexpected and was very confusing at first. When the scientists were able to study it more once they realized it was a hiatus, it became more evident that the sulfate aerosol emissions that us humans were producing. The skeptical science website and the article by Jeff Tollefson both seem relatively reliable. I personally felt like the article used more facts and science to make complete sense out of the subject. Tollefson is a reporter for Nature magazine, which is a well known and highly reliable source.

Feedbacks- What Exactly Are They?

Feedbacks can be hurtful and push the climate more towards global warming, but they can also be helpful by cooling the planet and attempting to balance global warming out. Feedback occurs when a change in our climate causes another change in climate. There are two kinds of feedback, positive and negative. Negative means that the feedback is going against the trend in climate. This means that if the globe is warming, this feedback would cause the climate to cool. A positive feedback means that the feedback further pushes the current trend of the climate. If the climate was warming, this feedback would further push the climate towards warming. Feedbacks have the ability to dramatically effect the climate, which is what makes them so important. The more that scientists understand about feedbacks, the more that they are able to make future climate predictions. The ice albedo feedback refers to the light that is reflected on Earth's surface, which is a positive feedback. This means that surfaces that have a higher albedo like ice and snow will reflect more sunlight into space. The Arctic is an example where the snow is melting due to global warming. The land and ocean absorbs more energy, which in turn causes the globe to warm even further. As the globe continues to warm, more land is exposed which is causing global warming to get worse.

Source: here

Ice Cores and Why They're Awesome!

The cool thing about ice in the arctic and other cold areas is that snow/ice layers on top of each other throughout the year. The snow and ice tell a lot about the temperature because in these frigid areas, the snow and ice don't actually melt. This allows the people analyzing the ice to help determine temperatures and climate of that certain layer. The snow varies in chemistry, as well as winter snow being different than the summer snow. Light and heavy oxygen can be found within the ice cores which can help indicate the climate and atmosphere for that time period. The snowfall collects dust, human pollutants, sea salt, ash and gas bubbles which then get preserved and can now be analyzed. Ice cores can be used to reconstruct temperatures, precipitation, volcanic eruptions and even forest fires. The way that ice cores are formed allow them to be easily read by showing distinct seasonal markers.

An example of an ice core is below:

Source: here

Ocean Sediments---Looking for a Job!

Ocean sediments looking for a job! Help-out the poor ocean sediments and create a Linkedin profile for them. You can do that directly in Linkedin and post the link on your blog or create a blog post with what you would post on Linkedin.

• Why are you special?

I am special because I am found within the ocean, which is a large portion of the Earth. This means that there is a lot of information that I can share. I can be found in the shells of tiny animals and plants that had a calcium carbonate shell.

• What skills, expertise, and characteristics do you have?

I can tell a lot about the chemistry as well as the temperature of the ocean. I also have the ability to tell you a lot about wind and water currents.

• What sets you apart from other job candidates (aka proxies)?

I can tell a lot of different things that other proxies cannot, mostly about the ocean. This means I can show when the ocean was cold and when it was warmer. I can also tell the chemistry of the water at certain periods in time.

• What are your ideal challenges where you can really excel?

I would like to be able to characterize the oxygen levels in my sediments. Oxygen can either be heavy or light and I would like to sort it in to categories, which I am very good at. I would also excel at dating these oxygen samples.

• Where would you like to work?

My ideal place to work would be on the ocean floors, I feel like I would be able be most beneficial if stationed there.

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