Exam 2 study guide

What are the data missing in current global circulation models (GCM, long-term climate models)?

Some of the data that we are missing is what is going to happen with some of the feedbacks. We do not have a really good understanding of the dynamic ecosystem thing, how fast the glaciers will melt in Antarctica and Greenland (this is critical for understanding long term models). We have projections of the Greenhouse Gases, but a lot of the feedback loops are not really understood and are not incorporated in the models as thoroughly. The Aerosols are included in the models now, we did not have them in the past but now we do.

*What causes an El Niño year?

Warm countercurrent to Peruvian current (appears in Christmas season), Last only a few weeks normally, Every 3-7 years they persist. Trade winds weaken + allow warm + nutrient poor water back to east Pacific which stops Peruvian current. This produces a very small El nino around christmas time. In an El nino year the trade winds really weaken and warm water comes back from the west. This shuts down Peruvian current for many months, even sometimes over year.

Beate Liepert found the same thing in Germany. She started looking through meteorological journals and records all over the world. Drops in sunlight were reported as ? for Antarctica, ?for USA, ?in parts of Russia, ? in parts of UK.

9% for Antarctica, 10% for USA, 30% in parts of Russia, 16% in parts of UK.

What seems to be the most likely RCP you will experience in your lifetime, and why do you think so?

Most likely RCP: 4.5 or 3 degrees of warming

IPCC statements have increased in certainty and level of alarm over the years. 2001 report?

Most of the warming in the past 50 years is likely due to an increase in GHG.

IPCC statements have increased in certainty and level of alarm over the years. 1990 report?

Observed warming is consistent with models, but AGW is still uncertain.

What are the data included in current global circulation models (GCM, long-term climate models)?

Ocean circulation model, Atmosphere-ocean coupling, ice-albedo feedback (Arctic sea ice seasonality added in 2008), soil moisture on land, changes in rainfall (affect ocean salinity, currents, albedo of land surface, Mathematics is the same as weather forecast

What is the difference in biological impacts of 1.5°C vs. 2.0°C warming? (species changes)

Of 105,000 species studied, 6% of insects, 8% of plants and 4% of vertebrates are projected to lose over half of their climatically determined geographic range for global warming of 1.5°C, compared with 18% of insects, 16% of plants and 8% of vertebrates for global warming of 2°C

What may be the explanation for the hiatus period when warming slowed in comparison to both before and after the hiatus?- PDO

- Warm PDO caused swift rise in temperature 1970-1999 - Negative PDO is cooling period of ocean + takes heat out of the atmosphere; slower temperature rise seen aka hiatus period

What do weather forecasters need to forecast the local weather?

- Weather forecasting today requires sophisticated models, initialization data from all over the world, and supercomputers - For a forecast several days in advance you need global initialization data.

The instrumental record and reconstructions of climate indicate that the climate has warmed 1.0 °C (1.8 °F) in the last 150 years. What evidence do we have that this seemingly little bit of warming has made a significant difference to life on earth already?

-Ocean and atmospheric warming -Coral bleaching, forest fires -Some evidence of health risks from vectors of mosquitos moving northwards -Heat waves that have killed tens of thousands of people. -Atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen and the concentrations of greenhouse gases have increased. -Look at examples of how the ocean levels increasing has impacted India (guest speaker) -Intense hurricanes - drought/famine

The drop in irradiance in the Maldives was due to two factors. What are they?:

1) the direct shading by the particulates from burning fossil fuels 2) these particles nucleated water into clouds, and made for clouds with many more droplets, which are more reflective. Satellites showed it was a world-wide phenomenon

Crux of the problem: GHG have been causing warming, while particulate pollution has been causing cooling. The middle of the road is what we have seen over the past 30 years. As we correct the particulate pollution problem, we will exacerbate the warming. The forcing from GHG is 2.6-3 watts of warming. Particulates are now thought to cause _______?_____ watts of cooling.

1.5 watts of cooling. If we correct the particulates, we will accelerate the warming if we continue to burn fossil fuel.

The Maldives is a nation of tiny Islands in the Indian Ocean that runs over a 1000 miles north and south. Veerabhadran Ramanathan led an effort to study sunlight and climate over the Maldives from the northern islands, which have pollution from India, and the southern islands, which have a clean air mass from Antarctica. There was a ______?_________% decline in sunlight due to pollution.

10%

Stanhill coined the term global dimming, on average a fall of ? in radiation reaching earth.

2-4%

If all nations meet their Paris Accords pledges, how much warming will we likely see?

2.7°C of warming

Why can't we theoretically get an accurate weather forecast past a 20 day forecast?

20 day forecast is theoretical limit because of errors in initial data = atmosphere too chaotic - magnifies errors) - ensembles are created to combat this chaos

What is the alarming significance of realizing the cooling effect of aerosols when we contemplate future warming?

Aerosols block sunlight from reaching the earth causing cooling, The cooling caused by aerosols helps offset the impact of climate change. Reducing aerosols and losing its cooling effect can increase the warming effect of climate change

what is the difference in biological impacts of 1.5°C vs. 2.0°C warming? (global terrestrial land area)

Approximately 4% of the global terrestrial land area is projected to undergo a transformation of ecosystems from one type to another at 1°C of global warming, compared with 13% at 2°C. This indicates that the area at risk is projected to be approximately 50% lower at 1.5°C compared to 2°C.

What has happened to arctic sea ice over the past forty years, and what is projected for the future?

Arctic Sea ice has been melting at a fast rate and is expected to continue to do so. Thick, multiyear ice buildup melts and is replaced by thin one year ice. 1979 - first satellite pictures 1989- half was multiyear ice (7 million square km) 2007- summer sea ice dropped 26% from 2006 2012- 3.5 million square km survived until September Thin ice breaks up more quickly- Ice free summers predicted 2020-2040

*What are the consequences for the climate of earth when we have an El Niño?

Block the upwelling, hurts the anchovy fishery, Have global effects on weather, 1982-83, 1997-98, 2015-16 strongest El Niño's in history, Storms in California, Heavy rains in Gulf, Quiet hurricane season, Warmer than normal winters, Coral Mass bleaching events

What are the climate implications for SRES?

CO2 Most to least projected CO2 emissions by 2100: A2 B1 is the least CH4 (taken from Fig 6.1 in "Lecture 10"):

What is CO2e and when will it likely double (from pre industrial levels)?

CO2e is the convert effect of other GHG to their effect in terms of carbon dioxide. The doubling of CO2e will take place in most scenarios around 2050

On September 12, 2001: Planes were grounded, weather was unusually clear and sunny. David Travis had been studying whether or not vapor trails of airplanes were having an effect on weather. What changed by over 1°C in just this short period?

Change in temperature range was just over 1°C higher than what it typically was.

India is facing some unique challenges with climate change. What will they experience that we will not? Focus on the unique things, that we have not experienced here or talked about. (essay)

Climate change in India will have many detrimental impacts on the country from many different aspects. One of the impacts that will be detrimental will be on the human population itself. Human health will be especially vulnerable due to different diseases. One example of this is that there will be more incidences of malaria/dengue in areas that are already prone, and introduced into new areas. Populations will be more vulnerable and sensitive to the monsoon season. There is marked increase in both rainfall and temperature over the 21st century projected. There is also expected to be a rise in sea levels. The behavior of the monsoons is not well-regulated, it is erratic. Additionally, there is expected to be warmer winters in India, La Nina events may be getting hotter than El Nino. Examples of this include Angul and Bhubaneswar in Odisha, for example, which have crossed the 40 degree Celsius mark in February 2021. Mountain states of Uttarakhand and Himachal Pradesh experienced temperatures higher than normal even in January — the time of the year usually characterised by biting cold. There have also been storm surges along with the sea level rising (mean sea level rise for Mumbai slightly less than 1mm/year and a possible decrease at Chennai, but no info on land movements). Agriculture in India is also a part of the vulnerable population.

Know the four SRES emission scenarios for the next 85 years, including the three variants of the A1 (A1F1, A1B, A1T) well enough that you could recognize them correctly in multiple choice or matching type questions. what is B1?

Convergence + service/information economy; rapid economic growth + shift to info economy; peak population mid century; global solutions, less CO2

*Give the most serious negative impacts expected with substantial climate change. Give enough detail that I can tell you understand what is likely to happen.

Coral reefs and Amazon forest. Sea level rise is very much a concern of the nations of the world, because they are going to cause major flooding and instability; climate disaster refugees which will lead to further political instability. Heat waves will kill people, so that can be considered one of the more serious impacts. Increasing frequency of hurricanes will also impact people's lives and properties. *No right answer say what you think is the most serious and give enough detail on what you think is the most serious, and why it is going to happen (detail on why it is the most serious) - he needs to know what the impacts and implications are going to be; basically have an answer and be able to back it up with evidence. Climate instability + climate refugees Loss of life-- heatwaves, hurricanes, etc. Famine, drought, etc.

what is the difference in biological impacts of 1.5°C vs. 2.0°C warming? (impact on coral reefs)

Coral reefs are projected to decline by a further 70-90% at 1.5°C with larger losses (>99%) at 2°C

GWR article about ocean acidification: author

Elizabeth Kolber

What are the best estimates of warming over the next century (from pre-industrial levels) with and without the uncertainties?

Estimates range from an increase of 1.6-4 degrees C from 1980-1999 levels by 2100 OR an increase of 2.1-4.5 degrees C from pre-industrial levels by 2100. In general, the range of uncertainties due to feedback loops is 1-6 degrees C.

IPCC statements have increased in certainty and level of alarm over the years. 1995 report?

Evidence suggests that humans are having a discernible influence on the climate (but still uncertain).

India is facing some unique challenges with climate change. What will they experience that we will not? Focus on the unique things, that we have not experienced here or talked about.

Extremely high winter temperatures Landslides Locusts

What is an SRES?

Includes economic + social scenarios

What is the impact of the IPO when it changes from negative to positive?

Positive- warmer than average tropical Pacific, cooler northern pacific; Negative- cooler than average tropical Pacific + warmer than average northern Pacific.

This includes some understanding of what the jargon associated with these means.

Growth & Convergence, Heterogeneous world etc. Know what these terms mean.

Know the four SRES emission scenarios for the next 85 years, including the three variants of the A1 (A1F1, A1B, A1T) well enough that you could recognize them correctly in multiple choice or matching type questions. what is A2?

Heterozygous world; individual countries are self reliant; continual population growth; technological and economic change is slow; poor stay poor + rich get richer

What kind of an impression did this make on climate science?

His results were ignored.

Which do you feel is our best chance at achieving 1.5, and why?-- which one do you think we can do?

I think P2 is our best chance because it has a slower decline but also a little overshoot to help us out until we figure out how to get rid of the overshoot

IPCC statements have increased in certainty and level of alarm over the years. 2007 report?

It is very likely that anthropogenically-produced GHG caused most warming since the mid 20th century, as well as affecting circulation patterns and temperature extremes.

Know the four SRES emission scenarios for the next 85 years, including the three variants of the A1 (A1F1, A1B, A1T) well enough that you could recognize them correctly in multiple choice or matching type questions. what is B2?

Local solutions; continual low level population growth; intermediate service economy growth; less rapid but more diverse tech; local environmental and social equity All pathways exclude global climate initiatives like the Kyoto Protocol, Copenhagen Accord, UN Conventions, Paris Climate Agreement, etc.

What are the climate implications for RCP scenarios?

RCP8.5: 8.5 W/m² or about 1370ppm CO2 by 2100 RCP6: 6 W/m² or about 850ppm CO2 by 2100 RCP4.5: 4.5 W/m² or about 650ppm CO2 by 2100 (many scenarios gave this result) RCP2.6: peak of 3 W/m² or about 490ppm CO2 before 2100, then decline to 2.6 W/m² or around 430ppm CO2 Most to least projected CO2 emissions by 2100: RCP8.5 - RCP6 - RCP4.5 - RCP2.6 Most to least projected CH4 emissions by 2100: RCP8.5 - RCP4.5 - RCP6 - RCP4.5 Most to least projected N2O emissions by 2100: RCP8.5 - RCP6 - RCP4.5 - RCP2.6

How do RCPs differ from the SRESs?

RCPs → just look at how much GHG is in the air, if the CO2e gets to this level then we will have this much forcing etc. very straightforward SRES → look at it from a social & economic point of view as well, more encompassing, more speculative because you have to figure out what happens to the economies and the societies etc.

What is an RCP?

Representative Concentration Pathways; CO2 equivalency

How have such models been tested

Run the model for a number of years of simulated time and compare to current climate and the variability in the model must be similar to real climate variability (Models are robust with this comparison) Run the model to simulate past climates, 9000 years ago (different radiative forcing due to Milankovich cycle difference), Other time scales also tested (Models are robust with this comparison) Run the model to predict effect of perturbations (such as volcanic eruptions) and compare it to real eruptions (Models were robust when compared to eruption of Mount Pinatubo)

*What are the climate consequences of a La Niña year?

Temperatures in eastern Pacific (by South America) are colder than usual, Colder air in western USA, Greater snowfalls, More severe hurricane activity, Strongest La Niñas, 1973-76, 1988-89, 1998-00, 2007-08, 2010-11, La Niña has colder than typical surface ocean temperature in the tropics

In 1984, summer rains in the Sahel had failed for more than a decade. The Sahel usually gets a seasonal monsoon. The Atlantic oceans warm north of the equator in summer and clouds move north. Pollution from Europe caused more clouds to form and cool oceans north of the equator. Without the heat, the rain belt never made it north to the Sahel. This led to what world-recognized climate disaster?

The Ethiopean Famine is now considered to be the first major disaster due to anthropogenic climate change. China relies on monsoons as well (3.6 billion people depend on this weather pattern), and so this could be a very serious problem.

*Why are we concerned about freshwater resources?

The concern is that we are going to run out of water. It is drinking water, but it is also irrigation water. We use more water for irrigation than for our households. We are concerned about losing our drinking water, but there are places that are more concerned than we are, and they are rationing. Example: in West Texas they are recycling sanitary water and then drinking it. There are concerns of drought and concern of the snow packs running out, so people that rely on them melting and coming down from the mountain are concerned. We have some areas in the United States that have mandates; for example, in California they have restrictions. Water tables are dropping. Summer water is lost because all the ice melt occurred in early spring. Reservoirs are being emptied too soon.

*What ecosystem impacts cause the greatest concern, and why?

The loss of the coral reefs, amazon, and mass extinctions have caused the greatest concern. These areas are extremely diverse which puts them at the forefront of species extinction. The coral reefs are also critical because they fix excess calcium carbonate, they are nurseries for fisheries (loss leads to huge economic/social impact when people on islands can't get the food they need from these fisheries). The amazon is a huge carbon sink so if it is lost, we will have accelerated global warming because it is a source of CO2 when it burns.

Peter Cox is predicting what new level of possible global warming?

The maximum of warming predicted for 2100 is 5°C. Cox predicts a maximum of 10°C when particulates are taken into account (assuming we lessen the production of these).

*Why do the nations of the world care about a meter of sea level rise? What could be that bad about that little of a change? Why worry about coastal wetlands?

The nations of the world care so much about a meter of sea level rise because a small change can cause a very large impact, and the rate is only going up. The rise in sea level is leading to higher storm surges across the world which poses a large problem because half of humanity lives in coastal zones. For example, 10% of land in Bangladesh (which is home to 150 million people) will be lost with just a 0.5 m rise in sea level. This will increase to 20% of land lost with 1.0 m of sea level rise. Areas in the Nile delta of Egypt are also affected. By 2050, 12% of arable land in this region will be affected by 1 m of sea level rise. Coastal wetlands are important when looking at sea level rise as well. These areas are rich in biodiversity and contain a vast amount of fish for human consumption. These wetlands have already been lost to development at a rate of 0.5-1.5% per year globally. Wetlands also protect the coastline from storms There are millions of people that live on the coasts, land that is only slightly above the sea level. We will get intrusion of seawater with groundwater. Floods and storms etc. The people that live on coastal lands will be impacted which will lead to instability. Coastal wetlands house fish and a lot of fish nurseries and the wetlands protect those coastal lines.

What is this measure of weather, and why was it used?

The range is the difference in daytime high and night time low temperature. This occurred all over the USA (it means that in the day more sunlight came in and warmed the surface, but night-time temperature still cooled the same as normal). This was the largest temperature swing in the past 30 years.

IPCC statements have increased in certainty and level of alarm over the years. 2013 report?

The warming observed is unequivocal. Observed changes include increased GHG concentrations, melting snow and ice, and rising sea levels. The past three decades have been increasingly warmer than any decade since 1850. 1983-2012 is likely the warmest period of time in the Northern Hemisphere for the past 1400 years. It is virtually certain that the upper ocean (0-700m) has warmed from 1971-2010. The oceans have absorbed about 90% of the energy that has been released into the climate system from 1971-2010.

In the 1950s' in Israel, Gerald Stanhill measured how much sunlight was hitting the surface. He took these measurements again more than 20 years later in the 1980's. How much of a reduction in sunlight did he document?

There was a serious reduction in sunlight (22% drop).

What causes coral bleaching?

Thermal Stress → causes the coral bleaching, multiple days/weeks with the temp one degree celsius higher than the average Ocean acidification → prevents them from recovering from thermal stress

*Your friend's uncle lives in Texas and complains that it was so bitter cold a couple weeks ago that global warming could not possibly be real. Explain to him why climatologists think the cold weather that hit practically the whole USA was actually likely due to anthropogenic climate change.

To explain to your uncle why the cold weather in the USA is likely due to anthropogenic climate change, I would first start by telling him that it is most likely due to the record-breaking loss in summer ice in the arctic ocean. Sea water is absorbing more light instead of reflecting it back. Arctic amplification is caused by this. In order to look at what is exactly occurring, we can look at arctic oscillation, or "AO index". When the AO index is positive, air pressure is low in the arctic, leading to the strengthening of the polar vortex. When AO index is negative, air pressure is high in the Arctic, so polar vortex cannot constrain Arctic air masses from moving south. When polar air drops down, it brings frigid weather to areas such as the United States and in turn, warm air goes up to the arctic. So, in summary, when we experience these extreme cold events, the arctic is actually experiencing warming which shows that anthropogenic climate change is the cause of these events. La Nina year interacted with polar front to lead it further down

What kind of grid do we have for the initialization data set?

We typically have a grid of columns about 100 km on a side, and 1 km high, with 20-30 vertical layers (Arrhenius had a one layer model) - world wide grid needed for initialization data set, Satellite soundings give information on temperature and humidity in the different layers based on infrared and microwave radiation. These are released and give detailed information on the layers up to 30 km in altitude. Geostationary satellites track motion in clouds (wind patterns and clouds) To forecast weather, you need to have initialization data from all over the globe - What happens locally is influenced by the entire planet's atmosphere (3 day forecasts now fairly accurate)

The AO and NAO can interact. What happens to climate in the Northern Hemisphere when both are negative?

Weakens polar vortex. Warm weather in Greenland; cold weather in northern Europe; mild + wet weather in southern Europe. Cold weather in north america as well.

Given that we cannot forecast weather accurately past 10 days (at present), how can we have any faith in long-term predictions of climate change?

Weather is not climate. We have models to predict climate that include : climate feedbacks [water vapor (1.2), cloud-radiation (0.6), ocean-circulation (0.3)] Models have successfully simulated past climates Tested well over short term

Why are we concerned about the effects of warming on agriculture when we have access to water in aquifers to keep the land from drying out?

When the climate gets so warm, the crops do not set seed. The yield is much reduced so we won't get a good soy crop, corn crop etc. The amount of yield goes way down because of temperature. Basically, the heat is bad for the plants and their yield, despite the fact that there is water available. Yield is the main thing for this question.

what is the difference in biological impacts of 1.5°C vs. 2.0°C warming? (impact on arctic summers)

With 1.5°C of global warming, one sea ice-free Arctic summer is projected per century. This likelihood is increased to at least one per decade with 2°C global warming.

GWR article about ocean acidification: Ocean acidification would be better described as ...

a decrease in ocean alkalinity

GWR article about ocean acidification: Since the start of the nineteenth century, how much of the CO2 emitted by humans during that time has been absorbed by the oceans of the world?

about half.

When are we expected to reach 1.5°C warming?

between 2030 and 2052

GWR article about ocean acidification: When carbonic acid becomes more concentrated in sea water...

carbonate ion concentration is decreased

GWR article about ocean acidification: The calcified planktonic algae in the ocean are ...

coccolithophorids

What do we have to do to limit warming to 2.0°C?

decline by about 20% by 2030 in most pathways and reach net zero around 2075.

What do we have to do to limit warming to 1.5°C?

decline by about 45% from 2010 levels by 2030, reaching net zero around 2050.

GWR article about ocean acidification: When pteropods experience sea water that has been acidified by increasing CO2 concentrations they....

experience dissolution of their shells, which turn opaque instead of being clear

Know the four SRES emission scenarios for the next 85 years, including the three variants of the A1 (A1F1, A1B, A1T) well enough that you could recognize them correctly in multiple choice or matching type questions. what is A1?

growth and convergence; rapid consumer economy growth; population peak mid century; rapid technological growth; increased global interaction + convergence. Sub categories based on energy sources: Fossil fuels (AF1), A1B (balance); A1T (alternative energy), most CO2

why is coral bleaching a matter of concern?

home to millions of species & has very high species diversity >> lead to high extinctions 90% of reefs at risk by 2030, all by 2050

GWR article about ocean acidification: A molecule of CO2 produced from burning fossil fuels will produce how many times the heat in the atmosphere than what was released when it was produced?

hundred thousand times

GWR article about ocean acidification: About how many species live in and around coral reefs?

million

GWR article about ocean acidification: Ken Caldiera when testifying to Congress said our target for CO2 emissions should be zero. He likened this to the target rate for...

mugging of little old ladies

We have to cut down air pollution or we could experience changes in rainfall patterns and droughts. The particulates are also the main cause of what kind of health problems?

respiratory health problems. USA and Europe have cut particulate pollution. The Sahel has gotten better. But the pollution has been protecting us from accelerated global warming.

GWR article about ocean acidification: when Chris Langdon demonstrated that coral growth is dependent on percent saturation of carbonate ions (more carbonate more growth, less carbonate less growth), the response of the oceanographic scientific community was....

skepticism

Michael Roderick and Graham Farquhar found pan evaporation rate was falling in Australia. During the 1990's the rate of evaporation was falling while the temperature was going up. They concluded temperature was not the most important factor in evaporation, indeed it is a combination of ________?________,_________?__________and ______?___________ that causes evaporation.

sunlight, humidity and wind