Week 5

Hi, all. Welcome back to WTW. What I think is the coolest part about my research project is that we are using different environments to simulate climate change, which I will expand upon in this post. Before I start, I want to acknowledge the danger of writing an explainer piece on climate change because so many of the effects are uncertain.  

The warmest year on record was 2016, but what does that mean? How do you measure the temperature of the earth? NASA and NOAA, which calculate this independently, takes in raw data from thousands of weather stations that measure temperature on the land, the sea's surface, and the Antarctic Ice Shelf.  With this raw data collected, they put it through an algorithm to estimate the global surface temperature (all of the data and methods are publicly available along with a bunch of pictures).  


Source: NASA

At this point, NASA and NOAA are subject to methodological criticism (there are some methodological disputes between the two agencies). One is that it is debatable weather the temperature of the ocean should be taken at the surface or deeper. Another is that weather stations may change their methods year to year. Even factoring in that uncertainty, it is unambiguous that the world is getting hotter.  This fact has been predicted since 1972 and known since 1985. The effects on animals, plants, ice shelves and seas that would happen if climate change was real are happening. 

Scientists have theorized that the release of carbon dioxide would increase the temperature of the earth before NOAA and even NASA existed. Why did they think that? 

In the 1890s (IMO, great years for math, not so much for science), a Sweedish scientist Svante Arrhenius tried to calculate the surface temperature of the Moon. Building off the work of scientists like Joseph Fourier, who calculated that Earth would be colder if it did not have an atmosphere, and John Tyndall, who found that carbon dioxide blocks in infrared radiation (what comes from the sun), he calculated that increasing the carbon dioxide of an atmosphere would cause a planet or moon to warm significantly.

Scientists could see the carbon dioxide content increase in the 1950s by performing spectroscopy. Wooh, spectroscopy! This was validated by looking at corals and ice cores. 

However, tying together carbon dioxide content in the atmosphere and global warming theoretically was easy (not to discount Arrhenius's work) when compared to empirically proving causation.  

How was causation proved? Looking at ice cores in Antarctica. Each year, snow falls on ice sheets and forms a new layer. When a long sliver of ice is extracted from the ground, it is like a time capsule because it contains information about each year's snow. It tells you stuff like the CO2 concentration in the air each year and the temperature. The data, which spans over hundreds of thousands of years, shows carbon dioxide concentrations and antarctic temperatures mirroring each other. At last, we see a link.



Might this only apply to the antarctic? Unlikely, but maybe. Is this indisputable proof? Unfortunately, no. But with the theory checking out and the data checking out, there is no doubt that carbon dioxide is causing global surface temperature to rise. 

Thanks for reading this longer than usual blog post. This is only half the climate change story (why should we care about climate change? What can we do about climate change? What does this have to do with plants and water); for the rest, you will have to come back to WTW.