2.2 Consequences of global climate change

The implications of climate change: changes to the hydrosphere

Source: https://www.oecd.org/env/cc/39721444.pdf

Follow the links bellow for more info on the imparct of climate change driven sea level rise and floods:

Sea level rise will double coastal flood risk worldwide

Global sea levels are rising fast, so where does that leave the cities most at risk?

RANKING OF THE WORLD'S CITIES MOST EXPOSED TO COASTAL FLOODING TODAY AND IN THE FUTURE Executive Summary

Case study: the retreat of Swiss glaciers

Alpine glacier retreat pushing Europe closer to water crisis

The implications of climate change: changes in carbon stored in ice, oceans and the biosphere

The carbon cycle

Source: https://people.hofstra.edu/geotrans/eng/ch8en/conc8en/img/carbon_cycle_wiki.png

I. Carbon and the Global Carbon Cycle

• Carbon is a ubiquitous element on Earth. Most of the Earth’s carbon is stored in rocks, but this carbon is essentially inert on the 100’s to 1000’s year timescales of interest to humans.
• The rest of the carbon is stored as CO2 (carbon dioxide) in the atmosphere (2%), as biomass in land plants and soils (5%), as fossil fuels in a variety of geologic reservoirs (8%) and as a collection of ions in the ocean (85%). These are the “active” reservoirs of carbon of interest in this website.

II. How are the Global Carbon Cycle and Climate Change / Global Warming connected?

• The Earth is warmed by the Sun. This warmth is returned from Earth to the atmosphere in the form of heat radiation.
• Many gases in the atmosphere, including CO2, absorb the Earth’s heat energy and radiate in all directions. The energy radiated downward warms the surface and lower atmosphere.
• Adding more CO2 to the atmosphere means more heat radiation is captured by the atmosphere and radiated back to Earth.
• Methane, CH4, is another very important greenhouse gas that is part of the carbon cycle. This website addresses only CO2.

III. Humans add CO2 to the Atmosphere, Nature removes about half of it.

• In the 1990’s, humans added 8.0×1015 grams of carbon (1015 grams of carbon  = 1 PgC) to the atmosphere each year, primarily by burning fossil fuels (6.4 PgC/yr) and clearing land in the tropics (1.6 PgC/yr). The ocean took up 28% of this carbon, and the land absorbed 32%. Only 40% remained in the atmosphere to cause climate warming.
• Natural processes are significantly damping the rate of carbon accumulation in the atmosphere.
• From 2000-2008, humans added 9.1 PgC to the atmosphere each year, 7.7 PgC/yr from fossil fuels and 1.4 PgC/yr from land use change. There is some evidence that a larger fraction of these recent emissions has remained in the atmosphere (45%, LeQuere et al. 2009).
• Future climate warming depends on both the CO2 source from human emissions and the CO2 sink from natural sinks in the ocean and the terrestrial biosphere.

IV. Carbon Cycle Applet

• With applet found on the next tab, you can develop your own scenarios for future human emissions and future carbon sinks in the oceans and on the land. Run the applet to see the impact on atmospheric CO2 and global mean temperature.

V. More information

• In the following tabs, you can also find basic information on the major components of the global carbon cycle. Under the links tab, you can find links and other resources for more information.

Source: http://carboncycle.aos.wisc.edu/

Read more at The carbon cycle: implications for climate change and the congress

Carbon stored in ice

A permafrost carbon bomb?

Carbon stored in oceans

The ocean plays an important part in the carbon cycle. Overall, the ocean is called a carbon ‘sink’ because it takes up more carbon from the atmosphere than it gives up.

Biological pump

Living things in the ocean move carbon from the atmosphere into surface waters then down into the deeper ocean and eventually into rocks. This action of organisms moving carbon in one direction is often called a biological pump.

Carbon gets incorporated into marine organisms as organic matter or structural calcium carbonate. When organisms die, their dead cells, shells and other parts sink into deep water. Decay releases carbon dioxide into this deep water. Look at the carbon cycle interactive to see how much carbon is in the deep ocean compared to other stores. Some material sinks right to the bottom, where it forms layers of carbon-rich sediments. Over millions of years, chemical and physical processes may turn these sediments into rocks. This part of the carbon cycle can lock up carbon for millions of years.

Source: https://www.sciencelearn.org.nz/resources/689-the-ocean-and-the-carbon-cycle

Carbon stored in the biosphere

All life is based on the element carbon. Carbon is the major chemical constituent of most organic matter, from fossil fuels to the complex molecules (DNA and RNA) that control genetic reproduction in organisms. Yet by weight, carbon is not one of the most abundant elements within the Earth's crust. In fact, the lithosphere is only 0.032% carbon by weight. In comparison, oxygen and silicon respectively make up 45.2% and 29.4% of the Earth's surface rocks.

Ecosystems gain most of their carbon dioxide from the atmosphere. A number of autotrophic organisms have specialized mechanisms that allow for absorption of this gas into their cells. With the addition of water and energy from solar radiation, these organisms use photosynthesis to chemically convert the carbon dioxide to carbon-based sugar molecules. These molecules can then be chemically modified by these organisms through the metabolic addition of other elements to produce more complex compounds like proteins, cellulose, and amino acids. Some of the organic matter produced in plants is passed down to heterotrophic animals through consumption.

Source: http://www.physicalgeography.net/fundamentals/9r.html

The implications of climate change: changes in biomes - case study - forest fires in the USA

Is Global Warming Fueling Increased Wildfire Risks?

Climate Change Has Doubled Western U.S. Forest Fires, Says Study

Forest fires burn 119,000 acres in 8 Southeastern states

The implications of climate change: changes to agriculture

Climate Change Impacts in the United States

The impact of climate change on people and places

5 Reasons Why Climate Change Is a Social Issue, Not Just an Environmental One

Understanding climate change as a social issue

Extreme weather events

As the world has warmed, that warming has triggered many other changes to the Earth’s climate. Changes in extreme weather and climate events, such as heat waves and droughts, are the primary way that most people experience climate change. Human-induced climate change has already increased the number and strength of some of these extreme events. Over the last 50 years, much of the U.S. has seen increases in prolonged periods of excessively high temperatures, heavy downpours, and in some regions, severe floods and droughts.

Source and more at: http://nca2014.globalchange.gov/highlights/report-findings/extreme-weather

Climate change: ‘human fingerprint’ found on global extreme weather

Case study - climate change in the Brazil

Climate change and human activities in Brazil with emphasis on the coastal zone

Synthesis and evaluation

Use the content from this post and linked articles to plan and answer the following question: 

‘Describe the uneven spatial distribution of effects and uncertainty about their timing, scale and impacts for individuals and societies ’. 10 marks

Use markscheme on page 56 from the new syllabus guide (AO3)