Climate Change Final

How do we know that variations in the Earth's orbit cannot be causing the current observed recent warming?

Orbital variations operate on too slow a timescale to explain present warming

Which of the following best describes equilibrium climate sensitivity (ECS)

The equilibrium change in global surface temperature that would result from a doubling of atmospheric CO2 compared to pre-industrial times

What is the IPCC's likely range for Earth's ECS?

2-4.5 degrees C

On Fig. 1 most curves are near zero past 8 C. This means:

ECS is very likely to be below 8 degrees C

(ECS is very unlikely to be above 8)

Owing to Fig. 1 what is the IPCCs most likely value for Earth's ECS ((delta)Tf)

3 degrees C

The direct response to a CO2 doubling is a warming ^Ti= 1.2 degrees C. It can be shown that the total warming is this direct warming ^Ti modulated by various feedbacks:

Where f=Eifi represents the sum of all feedbacks (positive and negative). Based on the value of ^Tf you found in the previous question, what does this imply about f?

Positive feedbacks win over negative feedbacks

Positive feedbacks win over negative feedbacks. Another way of saying this is:

Processes internal to the climate system amplify man-made warming

Approximately what portion of climate scientists agree on the reality of anthropogenic climate change?

>95%

What do we mean by "balance as bias"?

Reporting two sides of every scientific issue, even if one side is not supported by evidence

What is the "Tobacco Strategy?"

Using doubt as a political tactic to stave off government regulation

Is the behavior of Jastrow, Steitz, Singer and Nierenberg an ethical concern?

Yes, because the used their credentials to disguise a political debate as a scientific one

What ideology motivated the behavior of these 4 men of science?

Free Market Fundementalism

A common climate denial myth goes like this: "Throughout geologic history, climate has always changed, long before they were humans. It's been warm enough for crocodiles to live at the north pole! Human actions cannot possibly compete with natural cycles" What is the best way to debunk this argument?

Climate reacts to whatever is the dominant forcing at a given time; right now the dominant forcing comes from greenhouse gases.

what are 21st century climate projections based on?

Global Climate Model (GCM) simulations and radiative forcing scenarios.

Fig. 2 depicts projected changes in hydrological extremes in the RCP8.5 scenario. Based on this graph, where are dry extremes projected to increase overall?

Subtropics, Midlatitudes

Based on Fig. 2, where are wet extremes projected to increase?

Everywhere

Globally speaking, anthropogenic global warming will make which extremes more likely?

Both wet and dry extremes

Fig. 3 describes the projected global warming for a given level of carbon emissions. Notice that the range of projections widens (fans out) with total emissions. This is because:

Models have different ECS values.

Many climate scientists have said that 2 degrees C is our maximum global warming allowance to avoid "dangerous human interference with climate." Owing to Fig. 3, which emission scenario (RCP) can safely keep us under this target?

RCP 2.6

Looking at the bottom panel of this figure, approximately how much CO2 can we emit before we reach that target?

1,000 PgC

Proven hydrocarbon reserves (oil, gas, and coal) are currently estimated at around 3000 PgC. Given your answer to the previous question, how much of this carbon does humankind need to keep it in the ground?

2/3

What do we mean by "climate velocity"?

The speed at which climate zones travel across landscapes or seascapes due to a changing climate.

Fig. 4 compares the rates of species extinction in three settings, past, present, and future. How much larger (approximately) is the current rate of extinction for mammals compared to the past?

100 times

Compared to the present, how much larger is this number projected to be in the "business as usual" climate scenario?

10-100 times

Why are biologists worried that humans are crafting a new mass extinction?

The current and projected rate of species extinction are many times higher than in the geologic record

Climate change is hardest on

the poor, because they don't have the resources to respond

What do we call "meeting the needs of our generation without compromising the ability of future generations to meet their needs?"

Sustainability

If humans drastically reduced emissions now, what impact would it have over the climate?

Little impact over the next few decades but curb the warming after that

The ocean is getting fished to depletion, logging is destroying the rainforest and the atmosphere is treated as an open sewer because of:

The economic incentive to abuse the public good

"The economic incentive to abuse the public good"

What is this effect named?

The tragedy of the commons

Open access resource problem.

Building a seawall in anticipation of sea-level rise is an example of:

Adaptation

Implementing a carbon tax is an example of

Mitigation

Putting mirrors in space to reflect incoming sunlight is an example of

Geoengineering

Mandating CO2 scrubbers on every industrial smokestack is an example of

mitigation

Re-building cities at higher elevation is an example of

Adaptation

Fig. 5 shows the result of a model inter comparison project: 11 GCMS were used to see what would happen if a solar radiation management strategy was implemented to offset greenhouse warming for 50 years, then terminated abruptly. What happens when SRM stops?

Temperature increases abruptly

referring again to Fig. 5 what happens by year 70?

Temperature increases at about the same rate as the CO2 only experiments

Why is this dubbed a termination problem?

SRM is only a temporary fix

Why is geoengineering associated with a moral hazard?

The existence of cheap cooling systems may deter from curbing greenhouse gas emissions

What environmental problem did cap & trade successfully solve?

Acid rain

Why is climate change a global policy problem?

(all)

Carbon pollution is not factored into the cost of fuel source

High carbon users pass costs to low carbon users

Its impacts are worldwide

Which of the following best describes a cap & trade policy?

A central authority sets a cap on the amount of pollutant that may be emitted and the market sets the price of the emission allowances

In a carbon tax policy, how are emissions reduced?

A central authority sets a price on carbon emissions, and market mechanisms force emissions down

What are the advantages of market-based mechanisms for pollution control?

They allow companies flexibility to abate carbon emissions at the lowest cost

What is a carbon dividend?

Financial compensation for a low-carbon lifestyle

A revenue-neutral carbon tax