Climate Change

Why do we call this section Dinosaur Apocalypse? Let’s look at the word apocalypse. The dictionary definition is: an event involving destruction or damage on an awesome or catastrophic scale. The end of the age of dinosaurs was certainly a catastrophe from my ancestor’s point of view. You might be thinking, “Wait a minute, the end of the age of dinosaurs was because a large meteor hit the Earth.” Well, that is correct. However, unless you were standing within a thousand miles or so of the actual impact, it wasn’t the meteor that killed you. It was the change in the climate.

And there are many scientists who will tell you that the meteor was just the final nail in the coffin, that there is some evidence that dinosaur populations were declining for thousands of years before the meteor struck. They think this decline was due in large part to changing climate. Things like massive volcanic eruptions and shifting ocean currents can cause climate changes pretty fast from a geologic perspective. A few thousand years is nothing when you remember that dinosaurs roamed the earth for about 160 million years.

A great deal of what you will read in this Climate Change section of Dinosaur Earth will talk about how climate has changed over the history of our planet. There were times when there was no snow anywhere on our planet and there were times when the Earth was entirely frozen except for a narrow band around the equator. Some people even forget that people walked to North America from Asia because much of the ocean water was locked in ice, lowering sea levels enough to expose land bridges. During this time people could also walk from France to England as there was no water in the English Channel.

I hope that what you read here will help you better understand how climate has changed over the 4.5 billion years of our planet’s history and how you, as humans, are creating changes that no other inhabitants before us, have been capable of doing.

Did a Changing Climate Shrink Europes Ancient Hippos?

Throughout the history of our planet the climate has changed dramatically many times. The vast majority of these changes take many thousands, or even millions, of years. The change in climate we are seeing now is one of the most rapid on record. In fact, changes this fast usually happen only when a catastrophe strikes, such as massive volcanic eruptions or a large object crashing into our planet. The effects of climate change on animals can be very noticeable. This is the story of how a warming climate affected some prehistoric animals in Europe - and it wasn't the first time this happened on that continent.

Giant German hippopotamuses wallowing on the banks of the Elbe are not a common sight. Yet 1.8 million years ago hippos were a prominent part of European wildlife, when mega-fauna such as woolly mammoths and giant cave bears bestrode the continent. Now palaeontologists believe that the changing climate during the Pleistocene Era may have forced Europe's hippos to shrink to pygmy sizes before driving them to warmer climes.

Species of hippo ranged across prehistoric Europe, including the giant Hippopotamus antiquus a huge animal which often weighed up to a tonne more than today's African hippos, said lead author Dr Paul Mazza from the University of Florence. While these giants ranged across Spain, Italy and Germany, ancestors of the modern Hippo, Hippopotamus amphibius, reached as far north as the British Isles.

Hippos were a constant feature of European wildlife for 1.4 million years, during the climatically turbulent time of the Pleistocene era, which witnessed 17 glacial events. The experience of such environmental changes would not have been without cost, and DrMazza and co-author Dr Adele Bertini, also from Florence, investigated the impact this changing climate may have incurred.

The research focused on fossils from across Europe, ranging from the German town of Untermaáfeld in Thuringia, to Castel di Guido, North of Rome, and Collecurti and ColleLepre in Italys Central Eastern Marche province. The fossils were compared to a database of measurements taken from modern African and fossil European hippos.

The German fossil from Untermaáfeld is the largest hippo ever found in Europe, estimated to weigh up to 3.5 tonnes, said Mazza. The Collecurti specimen was also large, but interestingly even though it was close in both time and distance to the ColleLepre specimen the latter specimen was 25% smaller. A final specimen, an old female from Ortona in central Italy,
was smaller again. It was 17% smaller than the Collecurti fossil and approximately 50% lighter.

The team found that a clear size threshold separated hippo specimens which heralded from different parts of the Pleistocene age. The hippos from the early Pleistocene were the largest ever known while smaller specimens
emerged during the middle Pleistocene. Larger specimens briefly reappeared during the late Pleistocene.

We believe the size difference was connected to the changing environmental conditions throughout the Pleistocene, said Mazza. The Ortona hippo, the smallest of the specimens, lived in a climate where glacial cycles turned colder, while cold steppes replaced warm ones across the Mediterranean.

The drop in temperature and rainfall during the Pleistocene caused significant changes to plant life across Europe resulting in an expansion of grassy steppes. Being grazers hippos may have been expected to thrive in this new environment. Unexpectedly they appeared to shrink, only re-attaining their past size during the warm periods of the late Pleistocene, when forests and woodland re-colonized the steppes.

During their time in Europe hippos were forced to live in habitats influenced by a general environmental trend towards cooler and drier conditions. In response hippos achieved giant sizes during warmer and relatively more humid stages, but became smaller, and even very small, under non-ideal environmental conditions.

While hippos are normally considered indicators of warm, temperate habitats this research shows that temperature was not only the controlling factor for their ancient ancestors, concluded Mazza. Our research suggests other factors, such as food availability, were equally important. Appreciating the importance of factors beyond temperature is of great
significance as we consider how species may adapt to future ecological and environmental changes.
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This study is published in the Boreas. Media wishing to receive a PDF of this article may contact [email protected]
Full citation: Mazza. P, Bertini. A, Were Pleistocene hippopotamuses exposed to climate-driven body size changes? Boreas, Wiley, October 2012, DOI: 10.1111/j.1502-3885.2012.00285.x

Science is Real, And so is Climate Change

Did you ever need to take some medicine and you didn’t want to? You think that it is going to taste bad? Or, even worse, you had to go to the doctor and get a shot because you were sick and you knew it would make you better but you still fussed and hollered because you hated the idea of getting a shot? Well, it is kind of like that with climate change.

Think about this. When you go to a doctor to get a shot, the medicine that is in the needle that will make you better was made by scientists. Those scientists studied what it was that makes people sick and figured out how to make medicine that would fight the germs - a virus or bacteria - so the sick people would get better. Sometimes scientists are able to completely wipe out a disease, like smallpox, that used to kill millions of people. We trust those scientists because they spend many years studying the disease and understanding how it works so that they can find a cure. This is part of the reason that people live so long. Two hundred years ago people only lived half as long as we do today. Our longer lives are because of science and scientists!

What does this have to do with climate change? Well, I will tell you (you know I was going to, didn’t you?) For nearly 60 years scientists have been studying climate change. At first, only a few scientists were interested in how climate has changed and how it continues to change. That is because there wasn’t much change going on that we could see. And it was also because 60 years ago there were less than half the people on our planet than there are today. People were putting far fewer gases into the atmosphere than they are today. Over the years, as more evidence of climate change became obvious, more scientists began to study it. Today, there are thousands of scientists all over the world who study climate change. And what do you think nearly every one of these scientists believes? First, I will let you read their own words. And remember, this was written and approved by over 300 scientists from all over the world after many years of research, not just a couple of guys making stuff up.

“It is extremely likely that human influence on climate caused more than half of the observed increase in global average surface temperature from 1951 to 2010. There is high confidence that this has warmed the ocean, melted snow and ice, raised global sea levels, and changed some climate extremes in the second half of the 20th century.”

So, what are they saying? They are saying that people are responsible for more than half of the climate change we see all over the world. Glaciers melting in Greenland and in the mountains of India and Nepal, islands beginning to disappear in the oceans, hurricanes and tornadoes that are stronger and more destructive in North America.

Some people still don’t want to believe this. Just like some people will fuss about going to the doctor to get a shot even though they know it will make them better, some people don’t want to do what it will take to reduce their contribution to climate change. Even people who believe climate change is really bad still do things that contribute to climate change. They drive big cars that put greenhouse gasses into toe atmosphere instead of driving smaller, fuel efficient cars. They fly in private jets that use much more fossil fuel to move a single person than a jet carrying lots of people. They just don't want to take the medicine they know is good for them.

When i say that science is real, I am trying to make sure you know that there is no longer any doubt that at least half of climate change is happening because of how humans live. It happens because of the use of fossil fuels like the gas in your car, the coal that makes the electricity that runs the computer you are threading this on or the stove that cooks your food. The good news is that some of you - not very many - might have a house that runs on solar energy, or maybe wind energy. These are ways to create the power that we need that don’t produce the gases that contribute to climate change.

In closing, let me just remind you that not all climate change is caused by people. But if you don’t believe that SOME climate change is caused by people, you are just plain wrong and you aren’t looking at the science. Science is real!

Climate change learning material