Ordovician Period

When I first started reading the article on the Ordovician Period, I got to the mention of Gondwana, which made me stop and wonder, "Wait, haven't we been through this breakup before?" And the answer is yes, we have, in the blog I wrote about the Paleozoic Era, which the Ordovician Period is part of. I had to remind myself that this is not really déjà vue, that the Paleozoic Era has 6 periods to it, and my blog on the Era would have been like an overview, while the blogs on the periods would have more details. So, some of the big events, like the breakup of Gondwana, will be mentioned in both posts.

The Ordovician Period spans 41.6 million years, from the end on the Cambrian Period some 485.4 million years ago to 443.6 million years ago.

Life continued to flourish during the Ordovician Period, although there was an extinction event at the end of the period. The Ordovician Period is known for its biodiversification event, which considerably increased the diversity of life. Invertebrates, namely molluscs and arthropods, dominated the oceans, although fish, the world's first true vertebrates, continued to evolve, and fish with jaws may have first appeared late in the period. Life on land had yet to diversify.

However many meteorites strike the Earth in a year today, there were 100 times that many hitting the Earth per year during this period.

The southern continents were collected into Gondwana, which started the period in equatorial latitudes but then drifted toward the South Pole. Meanwhile, other continents, Laurentia (part of North American), Siberia, and Baltica (northern Europe), were drifting north, and Baltica started moving towards Laurentia later in the period. Another small continent, Avalonia, separated from Gondwana and began moving north towards Baltica and Laurentia.

Temperatures were mild in the early and middle Ordovician Period, but from 460-450 million years ago, volcanoes along one of the oceans spewed massive amounts of carbon dioxide (a greenhouse gas) into the atmosphere, turning the planet into a hothouse. These volcanic island arcs eventually collided with proto-North America and formed the Appalachian Mountains. [At last! I've been waiting for billions of years for the Appalachians to appear!]

Initially, sea levels were high, but as Gondwana moved south, ice accumulated into glaciers and the sea levels dropped. At first, low-lying sea beds increased diversity, but later glaciation led to mass extinctions as the seas drained and continental shelves became dry land. By the end of the period, the volcanic emissions had stopped. By then, Gondwana had neared the South Pole and was largely glaciated.

Reef-forming corals first appeared early in this period. Land plants probably evolved from green algae, first appearing in a form resembling liverworts. Fungi was also an early adopter of living on land, and facilitated the colonization of land by making mineral nutrients available to plant cells.

This period closed with a series of extinction events that are generally regarded as one major event, in which 49% of all fauna died. It is generally agreed that this event or series of events were caused by an ice age. That ice age had several pulses of increasing/decreasing glaciation. Each time the glaciation increased, the sea level dropped, killing many of the fauna that inhabited the shallow seas. When the sea levels rose during the next decrease of glaciation, there were entire families of fauna that had not survived to re-establish themselves in the shallow seas. This may have happened several times, producing a series of extinction events.

Well, now we're starting to get some place. Plants (of sorts) on land, starting to make the soil arable. Not sure about the carbon dioxide level in the atmosphere, but the meteor showers would be beautiful, as long as they didn't land too close. Hunting probably wouldn't do much good yet, but, hey, there's fish! Too bad I can't stand fish.

Maybe the next period will be even more amenable?

 

https://en.wikipedia.org/wiki/Ordovician 

Kenorland

Not to be confused with Kennerland, a theme park (based on a toy company) I just made up when I stumbled across the name of this supercontinent.

Kenorland was one of the earliest supercontinents, having formed about 2.72 billion years ago. It accreted some cratons that already existed, but also found some new continental crust to merge with. Pieces of it would later become Laurentia (most of North America and Greenland), Baltica (todays’ Scandinavia and Baltic regions), Yilgarn (Western Australia), and Kalaharia (large portions of South America and Africa).

It is known that Kenorland sat in low latitudes until great underground magma surges started to cause tearing of the crust about 2.48 billion years ago. At about that time, Baltica straddled the equator and was connected to Laurentia (Canadian Shield), Kola and Karelia (2 pieces that have since rejoined with Baltica).

It is thought that the breakup of Kenorland may have been when the Earth shifted from tearing caused by magma plumes to the modern plate tectonics we know today. However, the discovery of an earlier continent and a supercontinent may indicate this transition occurred even earlier.

By 2.45 billion years ago, Yilgarn (Western Australia) was no longer connected to the other cratons, and Kola and Karelia cratons were also drifting away. Therefore, there was longer a supercontinent, and this was about the same time as the Huronian glaciation, which lasted up to 60 million years. Indications are that atmospheric oxygen rose from 0.1% to 1%. This increase in oxygen caused the virtual disappearance of the gas methane, which was oxidized into carbon dioxide and water.

Furthermore, the breakup of Kenorland generally increased continental rainfall, reducing the other greenhouse gas, carbon dioxide. Also, the solar output at that time was less than 85% of its current power, and all these circumstances together produced a runaway “Snowball Earth”, where average temperatures planet-wide fell to below freezing.

Wow, that’s a pretty drastic response to a supercontinent not being able to hold itself together.

https://en.wikipedia.org/wiki/Kenorland

Baltica

Despite my confusion over the location of ‘the Baltic States’, they are right where normal people would expect them; along the Baltic Sea. Somehow, over the years, my mind had decided that the otherwise-un-named Baltic states were located immediately north and northwest of Greece. However, I looked them up (for the sake of this blog), and boy, was I wrong. I had put these states in Eastern Europe, but way too far south.

The Baltic States (Estonia, Latvia, and Lithuania) are in Eastern Europe, snuggled up east of the Baltic Sea and west of the Ural Mountains of Asia. And that places them right on the protocontinent of Baltica!

So, yes, this is kind of related to the Supercontinents blogs, but I’m only going to explore this one little piece of crust. Sometimes it roamed around on its own. At other times, it gathered together with other pieces of crust. Right now, it is smooshed between NorthEastern Europe and NorthWestern Asia. Will it succumb and eventually be pushed under these larger plates, or will it somehow break free again? I don’t know. But let’s see what is known about it.

The thick core of Baltica is also known as the East European Craton and is more than 3 billion years old.

About 2 billion years ago, small pieces of crust started colliding. These included Sarmatia (which was the Ukrainian Shield and Voronezh Massif*) and Volgo-Uralia. That seemed to work pretty well, so about 1.8 billion years ago, they added Fennoscandia, which included the Baltic Shield.

Now, if I’m reading the articles right, about 750 million years ago, Baltica and Laurentia (most of North America) both rotated clockwise, bumped each other lightly and headed for the south pole. At some point (possibly 650 million years ago), it is postulated that Earth became completely covered in snow and ice. (Yes, Snowball Earth.)

It turns out that Siberia was located fairly close to the South Pole, too, and it apparently didn’t take long for Siberia to completely lose its cool. According to one theory, Siberia started having some severe volcanic eruptions, and the build-up of green house gases in the atmosphere from that source resulted in a complete melt-down of all that snow and ice in as little as 2,000 years.

Anyway, Laurentia beat feet and headed north, but Baltica remained in the south at least long enough to hang around Gondwanaland. After that, Baltica drifted north and approached Laurentia again. However, around 425 million years ago, Scotland-Greenland and Norway all collided together, forcing Baltica to look elsewhere for new continental buddies.

Just when you thought you’d found a friend. Poor Baltica.

* Now a piece of Central Russia

https://en.wikipedia.org/wiki/Baltica

https://www.google.com/search?q=baltic+states&oq=Baltic+states&aqs=chrome.0.0l6.4638j1j7&sourceid=chrome&ie=UTF-8

Boreal Forest

If you want to talk about a forest that is larger than the Amazon jungle, then you will probably talk about the Taiga, the Boreal Forest or the snow forest. They are all one thing, with different names used in different parts of the world. Some say it is one huge forest, stretching from Iceland through the Scandinavian countries, Russia, Mongolia, Alaska and Canada. It is a coniferous forest consisting mostly of pipes, spruces and larches. It covers 6.6 million square miles or 11.5% of the Earth’s land area.

The boreal forest has a subarctic climate, with a very large temperature range between seasons. Summers last 1-3 months, always less than 4 months, and any given 24 hour period during the summer will average 50 °F or less. In Siberia, the average temperature of the coldest winter month is between 21 and -58 °F. The ground being frozen for much of the year, or even permanently frozen, can restrict the growth of deep roots, thereby favoring shallow-rooted trees like the Siberian larch.

Despite these harsh condition, the plants in the boreal forest have a lower threshold to trigger growth, and thus they ‘wake up’ a little earlier than one would expect. Even so, the soil tends to be poor in nutrients. Fallen leaves and moss tend to sit on the soil for a long time in the cold climate, so their organic components are very slow to be added to the soil. Also, acids from the evergreen needles leach the soil, making it even less ‘appetizing’ for anything but lichens and some mosses. On the other hand, diversity of soil organisms is high, comparable to a tropical rainforest.

It seems surprising to me that in a world that is frozen most of the time, fire is one of the most important factors that shape the composition and development of boreal forest. Some members of the boreal forest won’t release their seeds until the pods have been exposed to fire, and I get that, but how does something covered in snow most of the time suddenly burst into flames? Obviously, there is something about the process that I don’t understand.

Most boreal forest fires are either high-intensity crown fires or severe surface fires. These are large, often more than 10,000 hectares (a hectare is 100 acres) and sometimes more than 400,000 hectares. Different areas of the boreal forest burn at different lengths of time; drier areas might burn every 50 years, while wetter areas only burn every 200 to 300 years. And when an area burns, it could take decades, even a couple centuries to get back to ‘normal’. So all that carbon dioxide (a greenhouse gas) that is released into the air when those trees burn takes those same decades or centuries to be absorbed into the growing forest again.

This is particularly important now, when so much of the boreal forest is burning. Even Greenland - which doesn’t have any boreal forest, but does grow grasses and scrub brushes when enough ice melts to expose ground to seeds being blown around by winds - is on fire. Alaska and Canada are experiencing horrendous fires in their boreal forestland. In northern Siberia, one fire covered 7.9 million acres (over 3 million hectares), and that’s only one fire of 11 (or more) burning in Russia.

It’s been estimated that these fires dumped over 50 million tons of carbon into the atmosphere in June (2019), and they are still at it. 16 million adult trees burn in a day in Russia’s boreal forest fires. The Earth is not ready to absorb that much carbon. If we planted more trees - billions of them - it would help, but possibly not before the climate changes even more in response to that much carbon and carbon dioxide having been freed to begin with.

We really can’t sit around and wait any longer. We have to start facing this problem, and we have to do it NOW. The sky is falling, and doomsday is just around the corner.

https://www.dailykos.com/stories/2019/7/31/1875681/-Fire-at-the-top-of-the-world-Earth-s-largest-forest-is-burning-and-it-won-t-be-coming-back-soon

https://en.wikipedia.org/wiki/Taiga

The Sky is Falling

If you follow me on facebook, you may have noticed that I have shared many articles on climate change and that I have started using the comment, “The Sky is Falling.”

It seemed more appropriate than saying, “The Boy Cried Wolf.” In that story, the boy is lying, only looking to introduce some excitement into his own life, without regard for the consequences.

Chicken Little, on the other hand, was telling the truth, as best he knew it. Something (a raindrop) had come down from the sky and hit him. He had never experienced anything like that before, so the logical conclusion was that something terrible was happening, the sky was falling! Chicken Little ran around the farmyard squawking his terrible news, trying to warn all the other farm critters.

Even that doesn’t exactly fit the problem of climate change. Chicken Little was very young and inexperienced. But it’s scientists who have been trying to warn the world’s population that the climate was changing far quicker than it should. They have lots of experience at studying climate and how it has changed in the past, and they have a pretty darn good idea where it’s headed.

In the past week, I have read several articles concerning the number and severity of heatwaves that have been happening around the world. Not only has the world been having more of them, not only have they broken records for daytime high temperatures, they’ve broken records for the highest low temperatures as well. That means that after a sweltering day, you don’t get much relief during the night, because the heat that has accumulated all day doesn’t dissipate fast enough.

I think Europe has already broken several summer records during a heatwave in June of this year. There’s no guarantee they won’t have another later this summer. Or this fall, or... whenever. A heatwave can happen at any time on the calendar, because it is a comparison between the present and what has been ‘normal’ previously.

The scientists don’t ‘think’ any particular place will start having a heatwave every year. But it could happen. After all, they wanted us to keep the warming of the Earth to 2°C or less. What are they saying now, that it’s officially reached a warming of 1.8°C? But in Europe, the temperatures reached +4 to +8°C over ‘normal’.

I don’t know about you, but I don’t get much done when the temperature gets to 95°F. I sure don’t want it to consistently reach 123°F. Or higher.

Maybe Chicken Little isn’t the best story for me to quote to try to get my point across, but it’s the one I can remember as the summer heat settles in. So I’ll keep squawking my warning and hope somebody is listening, because...

The sky is falling.

What is This World Coming to? 6

Food. We all need it. We all have our favorites. But what will be available for us to eat in the coming much-warmer world?

Like the topic of ‘climate change’, this sub-topic is just as broad a question and just as difficult to sort out.

My initial belief was that the tropics would probably become pretty uninhabitable. After all, at least one city in the Middle East has already come too-d****d-close to that with a temperature of 115°F with 50% humidity. Places that are NOT deserts could be even worse. Deserts at least cool off at night, because they don’t have any cloud cover to hold the heat in. But when the humidity rises, cloudiness increases, so that heat could be held close to the ground. Also, when humidity rises, that ‘drop-dead’ temperature is lowered. At least as low as 96°F.

But the more I’ve researched, the less sure I am of that. I recently spent a few days looking at the countries in Central America, because I figured they were definitely in the ‘heavily tropical’ part of the world. The thing is, Central America is pretty mountainous, so a lot of the land is actually ‘temperate’. The low-lying jungle might not be a place people would want to live, but the highlands could still be habitable.

Crops, on the other hand, might not like the new weather patterns that could come. Even without the global temperature rising, people living in those countries right now have trouble providing food for their families year after year. The rainy season and hurricanes can produce mud slides and flooding. If that doesn’t happen, they could lose their crops because of drought, like the one they’ve been suffering through the last few years.

Anthropologists believe the Mayan civilization crashed because of a severe drought. Now that area is facing another drought, and who knows how bad it will become? None of the articles I read mentioned wild fires like we’ve had in the western states, but will there come a time when Central American starts to burn?

These were my thoughts as I studied this particular area, looking for food crops that might not survive where they have been thriving and will need to be transplanted elsewhere. I don’t have any answers on that yet. The export crops grown here might be okay, as long as they can get enough water. I’ll have to research individual crops - for instance, bananas - in order to take a guess on their prognosis.

Still more to come!

What is This World Coming to?

I firmly believe in climate change. In my mind, it is here, and it’s going to get bad.

But I’m not here to debate that with anyone. So, for the purpose of this series of blog entries, let’s say I’m trying to figure out what could happen (climate-wise) in the next 50 years, and how it will effect the people who have to live through it. Well, try to live through it.

The sea level will rise. There has been and still is a lot of water on the Earth that is not located in the seas. It’s not a liquid, it’s solid in the form of snow and ice. Glaciers, sea ice, and so on. This has all been melting at an increasing pace, and probably will continue until snow and ice become rare items.

You can already see the sea level rising, if you look; Miami FL has streets that are underwater during high tides. Miami Beach, located on a barrier island that barely qualifies as dry land, is quietly raising its streets, particularly the ones that run along the edges of the island.

After Hurricane Katrina hit New Orleans, there was much talk of how badly the shoreline was being eroded. If I remember right, there is an oil refinery or some such that was built on the shore. Now it is pretty much an island, and the road leading to it may or may not be passable during high tides. Those tides even reach 5 or 10 miles inland, making it hard to get in or out of small towns that dot that road. The road, I understand, has been raised in a lot of places, making it even harder to navigate in those small towns.

Parts of Amsterdam in The Netherlands are 18 feet below sea level. Much of The Netherlands consists of land ‘reclaimed’ from the sea and thus below sea level. They did this by building dikes, dams and canals to control where the water could go. This will be an ever increasing chore, as the sea rises.

So I find myself wondering, what happens when the sea rise reaches that critical point, whatever it is? Will The Netherlands continue building their dikes taller, until they loom and cast an ominous shadow over the land they are intended to protect? Is that possible? Does it make more sense to raise the land they are living on? Is that possible?

At what point do people simply give in to nature and move to higher ground? Do those who are displaced get any assistance from their government, or do they have to abandon the home they’ve had for who knows how long, take what they can to some other place, and try to start over again? I suspect the latter, because the former would probably bankrupt any government.

Even if Earth’s population doesn’t grow beyond what it is now, it’s possible the concentration of that population will increase, because there could be less land for us to live on.

Well, with the next entry, we’ll continue with the water theme. Yes, there is more about water to think about.

Martian Shelter 3

Today, let’s take a look at the 3rd design for a Martian home:

3. A greenhouse-type structure constructed of multiple layers of plastic film, built in such a way that visible light could get in, but infrared light (heat) could not get back out. That type of glass is sometimes used in Earth greenhouses, and could plastic be any more difficult?

Seems a bit unusual, to think of living in a greenhouse. Houseplants are one thing, but to actually live in your garden? I suppose one could get used to it, as long as you don’t grow something that sets off your hay fever. And to avoid the ‘fishbowl’ feeling, you could erect walls in some of the more private areas, even if those ‘walls’ were only curtains.

Have they really thought this through? There’s still all that harsh radiation that doesn’t seem to be considered, and will multiple layers of flimsy plastic keep enough heat in during the Martian night? The dust on Mars gets blown around quite a bit, despite the thin air, and settles onto everything. The rovers using solar panels have to hunker down and conserve their energy whenever a dust storm comes along, some of which encompass the entire planet and last for weeks. If solar panels can’t get enough power to work, how will plants do in constant shadow?

Not too thrilled about this one, either. That under-ground balloon is looking better.

Like I said, no split-level ranches, no colonials or tudors. At least the concept of a greenhouse is familiar, so maybe we’ll find something we can wrap our heads around yet. You never know, the next one might be exactly what you want!

http://www.imagineeringezine.com/e-zine/mars-makeshelter.html