Global Climate Change Chapter 13-3

Global Climate ChangeChapter 13-3

Some of the infrared radiation passes through the atmosphere, and some is absorbed and re-emitted in all directions by greenhouse gas molecules. The effect of this is to warm the Earth’s surface and the lower atmosphere.

Some solar radiation is reflected by the

Earth and the atmosphere

Solar radiation passes through the clear atmosphere

Most radiation is absorbed by the Earth’s surface and warms it

Infrared radiation is emitted from the Earth’s Surface

The

Greenhouse Effect

We know about the effects ofGreenhouse Gases (GHG)1.Carbon dioxide*2.Methane* - CH4

3.Nitrous oxide* - N2O4.CFCs – chlorofluorocarbons**5.Water vapor

*These are increasing due to human activities, primarily burning of fossil fuels** Being phased out, but persist in the atmosphere for decades

Primary Pollutants

Secondary Pollutants

Sources NaturalStationary

CO CO2

SO2 NO NO2

Most hydrocarbons

Most suspendedparticles

SO3

HNO3 H2SO4

H2O2 O3 PANs

Most and saltsNO3–

Mobile

SO42 –

Examples of Greenhouse Gases Affected by Human Activities

CO2 CH4 N2O

Pre-industrial concentration 288 ppmv 848 ppbv 285 ppbv

Concentration in 1999 366 ppmv 1800 ppbv 312 ppbv100 year Global Warming Potential 1 21 310Atmospheric lifetime (years) 50-200a 12b 120

• The main thing that contributes to greenhouse gas emissions is the burning of fossil fuels since the Industrial Revolution

• How does the pre-industrial level of CO2 compare to 1999?

Source: Based on IPCC (1994)

CO2 C

once

ntra

tion

(ppm

v)

Year

380

360

340

320

300

280

260800 1000 1200 1400 1600 1800 2000

380

360

340

320

300

2801850 1900 1950 2000

CO

2 Con

cent

ratio

n (p

pmv)

CO2 Concentrations Over the Past 1000 Years

Data on ice core samples taken in Antarctica give us a picture of climate that goes back thousands of years

Map of the continent of Antarctica

Atmospheric gases and particles are trapped in the ice and can be analyzed to determine the composition of the atmosphere at different points in time. The deeper the core, the longer ago the ice was laid down. This one-meter long section of ice core from the West Antarctic Ice Sheet project shows a dark ash layer. (Photo credit: Heidi Roop)

Atmospheric carbon dioxide does vary over timeWhat relationship do you see between temperature and CO2 levels? Does one go up first?

What makes the temps go up in the first place?

Milankovitch cycles – periodic changes in earth’s orbit begin the warming periods (end of ice ages)

With warmer temps, more CO2 goes into the atmosphere from the oceans, which raises temps even more

This is called a positive feedback system

Look at this graph again.What is the highest level of CO2 in ppm over the last 400,000 years (except for the present)?

Current levels of atmospheric CO2 : higher than they have been in recorded history

http://co2now.org/

This data is from Feb. 2012

Latest data from Feb. 2013

Atmospheric carbon dioxide levels 1960-2000This graph is called the Keeling Curve – famous graph you should know!This is data collected at a station in the Pacific from 1960-2000Keeling was one of the first scientists to document the consistent rise in CO2

levelsNotice the yearly cycle going up and down – can you explain this?But overall, the trend is clearly upward

Time-lapse history of human global CO2 emissionshttp://www.youtube.com/watch?v=kqV-kx2ClXU&feature=related

So if CO2 levels are correlated with temperature, then we expect global temps to rise since the levels of CO2 have risen. And that is what we see…..

• This graph shows annual mean global temperature anomalies over the period 1880-2001. The zero line represents the long term mean temperature from 1880-2001, and the red and blue bars are showing annual departures from that mean.

As is evident in the graph, 2001 was second only to 1998 in terms of global temperature, and the trend has been toward increasing temperatures at least since the beginning of the 20th century. Land temperatures have greater anomalies than the ocean, which is to be expected since land heats up and cools down faster than water.

Global Warming Data from NOAA

Graphic showing global temperatures warming since 1880

http://www.nasa.gov/topics/earth/features/2011-temps.html

2010 According to NOAA scientists, 2010 tied with 2005 as the warmest year of the global surface temperature record, beginning in 1880. This was the 34th consecutive year with global temperatures above the 20th century average.

2011 NASA reports 2011 was the ninth warmest year on record

What about 2012? See next slide.

Year Global[63] Land[64] Ocean[65]

2010 0.6590 1.0748 0.50272005 0.6523 1.0505 0.50071998 0.6325 0.9351 0.51602003 0.6219 0.8859 0.52072002 0.6130 0.9351 0.49022006 0.5978 0.9091 0.47922009 0.5957 0.8621 0.49532007 0.5914 1.0886 0.39002004 0.5779 0.8132 0.48852012 0.5728 0.8968 0.4509

10 warmest years on record (°C anomaly from 1901–2000 mean)

2012 is in the top 10 warmest years, too.

What evidence do we have that human activities are the cause of global warming?Radioisotopes of carbon in the atmosphere have revealed that more and more of the carbon is the type found in fossil fuels, and a lower percent is the type of carbon that has normally occurred in the atmosphere.

IPCC – • Intergovernmental Panel on Climate Change • Established to be an objective source of information on climate

change for policy makers worldwide• made conclusions and reports based on many scientific studies• 2001 IPCC released third report – “states baldly that global warming,

unprecedented since the end of the last ice age, is ‘very likely’”; debate among scientists is effectively ended

• 2007 IPCC concluded with statistical certainty (90%) that human activity is contributing to global warming

See their report: http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr.pdf

Nobel Peace PrizeNobel Peace Prize was awarded in 2007 to Al

Gore, former Vice President of U.S., and the IPCC for work on the issue of climate change

What does global warming have to do with world peace?

Scientific consensus

There is scientific consensus that global climate change in happening and that human activity is the cause. There is not really any more debate in the scientific community. There are still a few people who are considered climate skeptics, but not very many. Some of these “contrarians” are the same people who were skeptical of and argued against the dangers of tobacco, the threat to the ozone layer, and the cause of acid rain – all of which have been scientifically proven to be true.See the book Merchants of Doubt and the website Union of Concerned Scientists for more information.

Consequences of global warming

1. Rising sea levels – due to (1) melting of glaciers and polar ice (documented already)(2) thermal expansion of ocean at warmer temps

How will this affect polar regions? Islands? Coastal cities?

Documented sea level rise from 1880-2000

Effects of a 1m rise in sea levelAreas in red will be flooded if sea levels rise 1m

2. Dwindling Arctic and Antarctic sea iceAnother example of positive feedback – as the ice melts, there is less white and more dark surface to absorb radiation from the sun. This is called decreased albedo, or reflectivity. Temperatures go up even more.

What does this tell you?

Since 1995 Reports of Antarctic ice shelves breaking up (predictions coming to reality)

3. Melting permafrostPermafrost is a carbon sink and when it melts, releases more carbon into the atmosphere, making global warming even worse – another example of positive feedback

Consequences of global warming

Studies have already documented that this is occurring.

4. Human health problems• More problems with mosquitoes, diseases they

transmit• Ground-level ozone increases, leading to breathing

problems

CLIMATE CHANGE

Temperature Rise 1

(Sea level Rise 2)Hydrologic Extremes

Urban Heat Island Effect

Air Pollution

Vector-borne Diseases

Water-borne Diseases

Water resources & food supply

Environmental Refugees

Heat StressCardiorespiratory failure

Respiratory diseases, e.g., COPD & Asthma

MalariaDengueEncephalitisHantavirusRift Valley Fever

CholeraCyclosporaCryptosporidiosisCampylobacterLeptospirosis

MalnutritionDiarrheaToxic Red Tides

Forced MigrationOvercrowdingInfectious diseasesHuman Conflicts

1 2°C by yr. 21002 49 cm “ “IPCC estimates

Source: Jonathan Patz, 1998

HEALTH EFFECTS OF CLIMATE CHANGE

Consequences of global warming

5. Changes in weather patterns, such as more severe storms, changes in precipitation

The frequency of downpours and heat waves, as well as the power of hurricanes, has increased so dramatically that "100-year storms" are striking some areas once every 15 years

Hurricanes increase in strength over warm water, could become more intense with global warming

Consequences of global warming6. AgricultureDecrease in crop yield due to drought, floodsSome areas will have higher yields due to longer

growing seasonIncreased need for irrigation

Consequences of global warming7. Effects on plants and animalsOrganisms in ecosystems are adapted for certain climate and if that changes,

plants and animals there may not survive (adaptation in plants and animals takes time and global warming is changing things quickly),

Ex: polar bear – threatened by loss of sea ice that is necessary for successful hunting,

Ex: golden toad of Costa Rica’s cloud forest – now extinct due to climate change there

Coral bleaching occurs at warming temps – only takes a sustained increase of about 1°C for corals to bleach

Healthy coral reef with high biodiversity

Bleached coral reef with low biodiversity

Current and Projected Ranges of Sugar Maple

Source: Redrawn from Davis and Zabinski, 1992

Present Range Overlap Predicted Range

Prediction based on increased temperature

Prediction based on increased temperature and moisture reduction

Consequences of global warming

UAB researchers have documented that king crabs, once absent from the Antarctic, are invading because the ocean temperatures are warmer. This is bad news for the species that live there which are not adapted to survive predation by shell-crushing crabs.

Consequences of global warming

8. Ocean acidification – • normal ocean pH is close to 8 but it is dropping due to addition of CO2 which

forms an acid in the water• Shelled organisms can’t handle the lower pH and are being affected• Sea urchin larvae don’t develop normally – UAB research

Consequences of global warming

Kyoto Protocol, 1997

International agreement to reduce greenhouse gas emissions

About 120 countries agreed, U.S. has not

U.S. objections: negative economic impacts, developing countries not held to same protocol as developed countries (not seen as fair)

Expires in 2012

Copenhagen Accord, 2009U.N. sponsors a yearly meeting of many of the world’s countries to discuss global climate change Recent outcome: Copenhagen Accord – non-binding agreement to combat climate changeSome of the main points:• Recognizes the scientific view that an increase of 2°C should be the limit in

order to combat climate change• Countries set goals to reduce in GHG emissions• Reduction in deforestation is critical• Endorsed continuation of Kyoto Protocol• Funding/incentives should be provided to

developing countries

Copenhagen Accord, 2009Criticism• Not a legal agreement• Was drafted by only 5 countries• Does not say where funding will come from• Sets no real targets for emissions reductions• Countries only “took note” of the accord, did not adopt it

Summary of global warming/cooling components:

What can we do to reduce CO2 emissions?

Increase energy efficiency – use less fossil fuelsUse cleaner fossil fuels, i.e., natural gasGovernment intervention – i.e., laws, tax incentives,

international agreements

Carbon sequestration

Also called Carbon Capture and Storage (CCS)

Cap and trade, or carbon credits

Develop and use alternative fuels that produce little or no CO2

More on this in the unit on energy

Summary video to end with….

http://www.youtube.com/watch?v=KYLGBIiq6Wg