Humans have made many changes to the world dimply by burning fossil fuels. This has changed the global carbon cycle. Since normally, the seawater absorbs the carbon dioxide which is soluble in the water, it gathers. This means there can be fifty times as much carbon in the ocean as in the atmosphere. This begins the backbone of organic molecules. This normally is used by consumers, decomposers and producers to convert the carbon into organic compounds which make it available to other parts of the food chain. Calcium carbonate may be deposited in coral reefs and biogenous sediments with this carbon. The sediments contain twenty five times as much carbon as the seawater. Sometimes, the calcium carbonate dissolves back into the ocean. Since we have put more carbon dioxide into the air, it will in turn increase the carbon amounts in the ocean and biogenous sediments, which are marine organism skeletons and shells, and in the coral reefs.
We don’t just affect carbon, either,we also are increasing nitrogen, primarily from fertilizers, burning fossil fuels and nitrogen-fixing crops. Normally, the nitrogen was in balance with the global environment, through denitrification, but now, humans have influenced the environment. This means that fixed nitrogen is increasing.
When there are fluctuations in the earth’s atmosphere, we have witnessed evidence of ice ages and geological active periods. The world is always changing. There were medieval warm periods from AD 850-1250 and a “little ice age” from 1500-1860. Incidentally, a few years ago a hosted a large, medieval feast focusing on the early years of the “little ice age.” Some of my research indicated there was a focus on crops which were resistant to water. However, like the text detailed, this was primarily a localized climate change. Climate refers to conditions over decades, whereas weather is short term. It has already been indicated that heat fluctuations can quickly change the ocean’s environment.
Although we didn’t always have the technology to measure temperature we have accessed the following for natural climate indicators:
Pollen
Historical record with geological and/or climate information
Tree rings
Ice cores
Corals
Ocean sediments
Boreholes in continental rock
Through these methods we are able to get a good foundation of what the world’s average temperature is. We can easily see there is a huge spike in temperature. Although the ocean slowly heats, it is heating, and the Arctic and Antarctic are heating faster than anywhere else. Between 1955-2003 it is estimated 84% of the planet’s heating has directly been increasing ocean temperatures. This has helped us to not heat up too fast. The United States National Research Council, United States Geological Survey National Oceanic and Atmospheric Administration have established the Intergovernmental Panel on Climate Change and scientists almost universally agree that the human activity has increased the results of the greenhouse effect.
The Greenhouse effect which normally helps warm our planet and keep it capable of supporting life, may be keeping too much heat on the planet. It makes it warm enough to have liquid water. By examining air bubbles trapped in ancient ice, we find there is little Caron dioxide change in the atmosphere. Around 1750 these natural balances went out of sync. The industrial revolution in the mid nineteenth century has modified cycle and Carbon Dioxide levels are very high. Higher than any other time, and it is still going up. This dissolves into the ocean, but the natural cycle cannot catch up and have resulted in the rise of Carbon Dioxide. Other greenhouse gases have also gone up, like nitrogen and methane. Humans have directly made this change. Burning coal, oil and more use, as well as getting rid of forests have all modified the world. Methane is also on the increase, and this may be from sheep, cattle, fossil fuels, landfills and rice patties. As the world warms, sea levels go up due to icecaps and glaciers melting. Although this is part of the natural cycle, it is going much faster than natural.
Since 1870 the sea level has averaged a 1.5 mm/yr (.06 in/yr) rise. This went up, however, between 1961 and 2003 to 1.8 mm/yr (.07 mm/yr) and suddenly in 1993 and 2003 the rising sea level was averaging 3.1 mm/yr (.12 in/yr). This has created snowfall in some areas, and melted entire sheets of ice in others. Scientists did not expect this to happen this soon. Pieces of the Antarctic are breaking off or melting. This eventually alters the sea level and glaciers make it to sea faster. In 2007, summer ice cover in the Arctic was lower than anything since 1979 and in 2011 it was even lower. It changes rainfall pattern, how the ocean is circulating and alters how fast or common storms are occurring. The presence of ice reflects solar energy, but the open ocean is dark and absorbs heat.
The planet is warming and it affects the animals. On land, half of temperate species have ben affected by global warming of the biosphere. As it is warmer, spring arrives faster and it changes when plants flower, frogs breed and even the migrations of birds. This affects sea animals too. The emperor and Adeilie penguins have gone closer to the south pool since they depend on sea ice. There are other penguins, the chinstrop and Gentoo which have waters where there is no longer ice. Krill are not as plentiful in Antarctic and the sea ice algae is also declining which affects the food chain.
Entire food webs are changing. Phytoplankton is the base of many food webs and it has declined. There are some areas the larval cod (Gadus morhua) in the North Sea are reduced in number. The warm water zooplankton that are now in the area are not suitable for cod and the cold weather zooplankton they are more suited to eat is reducing in number. In addition, zooplankton, and the phytoplankton they feed on are triggered by different indicators. Photoplancton has its spring bloom when daylight and light availability increase. Many creatures feed off of these beings to exist. They are al a valuable part of the ecosystem and their loss could impact creatures all over the world. Their reduced number has far reaching consequences.
Even if we stopped with any possible carbon emissions now, it would be decades of rising before it would go down because we have made a “warming commitment.” A few degrees warmer will make Earth warmer than it has ever been in 3 million years. Sea levels will continue to rise. It will speed up the water cycles and there will be an uneven distribution of rainfall and evaporation. This means floods, forest fires, and droughts will increase. Food yields are expected to decrease. Thus will affect our food supply. Coastal areas will be at risk from inclement weather.
Since Carbon Dioxide dissolves in the sea water, the acidity goes up. This also changes the way things work in the ocean. Some organisms are not as able to live as well. It interferes with creatures that have shells or structures of calcium carbonate. The Calcium Carbonate dissolves easier if the pH is lower. The ocean surface waters have a lot of it, so it doesn’t dissolve there, however, when the organisms have to live where the solubility is different, the shells form slower and its harder to do. It makes it hard to calcify and also reduces carbonate ions available. This also reaches all over the already stressed ecosystem. There is pollution and overfishing as well as damage to coral reefs which is already putting a strain on the ecosystem. It affects mussels, sea urchins, coralline algae, clams, snails, barnacles and more. Plankton also is affected, but luckily it grows better which helps a little. No one really knows how acidifying will actually affect the ocean. We have already taken lots of beings out of the ocean, a lot of it for food or food production. Habitats are disappearing. Alien species have also been introduced. Last year, in Lake county at Clearlake, a giant fish was found, it was an invasive big fish and someone just happened to catch it on a fishing line. It was probably someone’s pet who got too big and they set it free in Clearlake, however, in that region, which is said to have connections to the ocean, it has been “seeded” with fish for the fishing industry which have outcompeted many of the rare, indigenous species.
I think that many people will still think that it is all part of a cycle of the planet. Unless they look at the figures and understands how it affects the ocean, they may not realize how in particular it is modifying the planet. Since it has a far reaching impact on the ecosystem, it is a complex subject. It has many unique situations that most people would not know or understand without studying. It needs to be clear also, that climate change is not the only challenge facing the health of our oceans.
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