Klimadapt - 04-02: Rising sea levels

Observations show that since 1900 to the present day the level of the world oceans has risen by about 21 cm. Sea level rise is mainly caused by two factors related to global warming: added water from melting ice sheets and glaciers and the expansion of sea water as a result of its warming.

In the 21st century, as a result of the continuing global warming the pace is expected to accelerate further. The latest measurements show that sea levels are currently rising by 3.6 mm per year.

Learn more.

Open the online worksheet "Tuvalu: The First Casuality of Climate Change" or print and distribute a copy of this worksheet to students. Ask a volunteer to read the text. Then invite students to share their thoughts and feelings.

Ask the class to search the Internet for examples from other parts of the world affected by sea level rise due to global warming. Discuss what the implications might be for local people.

Tuvalu: The First Casuality of Climate Change

Open the online worksheet "Ocean Acidification" or print and distribute a copy of this worksheet to students. Ask a volunteer to read the text. Then invite students to discuss the information provided.

Encourage students to search the Internet for additional information about threats to coral reefs in different parts of the world's oceans. How would you comment on the fact that 25 percent of marine species are threatened with losing their habitats if corals die?

Some of the websites listed below can serve as a starting point when looking for more information on the threats to the future existence of corals posed by seawater acidification:

Ocean Acidification

Importance of the World Ocean

Write “World Ocean“ on the white board or on a poster. Organize an associations game and ask students to list the points of significance of the ocean for nature and man (regulator of climate and rainfall, source of food, salts, energy, many resources, ancient and modern road, place of recreation, environment of marine ecosystems, home of millions of biological species, cradle of life and others). Complete the answers. Don't forget to consider its importance as a primary carbon dioxide sink and its role in slowing down climate change. Organize a discussion and draw conclusions about the importance of the World Ocean and the need for its conservation.

Show the video "The Earth is Warming" to the class. Discuss the following questions:

Which daily-life people actions cause an increase in the temperature of the environment?
How does this rise in temperature affect sea level?
Is there a danger to people living in the immediate vicinity of the seashore?
Could each of us change something in our personal lives to limit the global warming of the planet?

Show to the students the NASA animated video "What Causes Sea Level Rise". Discuss the following questions:

What is local sea level and how is it measured?
How is the level of the World Ocean measured?
How many centimeters has the level of the World Ocean risen by in the last century and what is it due to?
What are the two main causes of sea level rise?
Which communities are affected by sea level rise?
Is there a danger of rising the level of the Black Sea?

Why is the World Ocean level rising?

The students in the class where George studies start an argument about what is causing the rise in the level of the world oceans:

According to Annie, this is due to the melting of the snow and ice from the Arctic and Antarctic.
According to Mikhail, the reason is the pollution of the oceans and seas, their excessive exploitation by humans.
Victor believes that ocean level rise is due to the thermal expansion of water.
For George, the reasons are probably in the increased number of intense storms and precipitation.

Organize a discussion on the given answers. Draw conclusions.

Ocean currents and climate

The Gulf Stream is a powerful, fast, warm, surface current in the North Atlantic Ocean that originates in the Gulf of Mexico. It is one of the most powerful currents in the world, having a significant impact on the climate of the eastern coast of North America from Florida to Newfoundland and the western coast of Europe. Scientists agree that thanks to it, the climate of Western and Northern Europe is warmer compared to other areas located at a similar latitude. In addition, the Gulf Stream causes the formation and development of powerful cyclones - both over the ocean and over the land.

El Niño and La Niña are natural phenomena that occur when the waters of the Pacific Ocean become unusually warmer or colder. El Niño occurs along the west coast of South America, and La Niña - not far from the Philippines. These ocean currents are strong evidence of the influence of the oceans on Earth weather and climate. Their periodic occurrence causes extreme climatic conditions and various natural disasters such as floods and drought in different parts of the world.

Task:

Research these ocean currents in more details on the Internet or other sources.
How often do they occur? What weather phenomena do people associate with them? How do their impacts affect the lives of the communities in the affected areas?
Is there a system developed to predict their adverse effects? Does the Gulf Stream affect Bulgaria's weather and climate?
Describe your research results into a report.
Create a poster illustrating your findings using photos and reprints from the Internet.

Ocean acidification

Experts say that oceans absorb around 40-50 percent of the carbon dioxide from the atmosphere. That is the reason to often call oceans “the planet biggest carbon sink”. Step by step oceans are becoming increasingly acid due to the increase of greenhouse gases and in particular – the carbon dioxide.

Seawater acidification has a detrimental effect on a number of plant and animal species. Shellfish are the most vulnerable. Supplement your knowledge based on Worksheet "Ocean Acidification", as well as through additional Internet research.

Conduct an experiment for the implementation of which you will need a chicken egg and a glass of vinegar. Try to simulate ocean acidification on calcareous skeleton by placing a raw chicken egg into a glass with vinegar (eggshell contains calcium carbonate) and leave it for 2-3 days. After that, examine the changes in the shell. What conclusions can be drawn?

Discuss the following questions:

Acidification is no longer a regional but a global problem. Which of your daily habits increases the concentration of carbon dioxide and thus causes the acidification of sea water?
What actions are needed locally and globally to reduce further ocean acidification?

How would you explain the message of the scientist Carol Turley from Plymouth Marine Laboratory: “Ocean acidification – it is a silent storm. It can’t be heard, it can’t be felt, it can’t be seen, but scientists are measuring it.”