# Presentation: 451782

## Konrad Cunningham, Joel Arberman, Nadine Bell, Susan Harder, Drew Schindell, Gavin Schmidt  

**The Effects of Climate and Emission Changes on Surface Sulfate Wet Deposition in 2030**

## Topics

- Climate Experiments
- Sulfates
- Sulfate Deposition
- Objectives
- Model Description
- Conclusions
- Ongoing Work

## Sulfate Aerosol In The Environment 

- Sulfate deposition leads to acid rain
- Affects of acid rain can have negative affects on ecosystems and human health
- Sulfate aerosols can influence climate change

## Sources of Emissions

- Natural Sources of sulfates
- 			Volcanoes
- 			Oceans
- Anthropogenic Sources (3/4 of tropospheric sulfate burden)
- Sulfates(SO4-2) are formed through several mechanisms from the precursor primary pollutant sulfur dioxide (SO2 )
**	****   **SO2 + H2O2     SO4-2    (occurs rapidly in clouds)
**	****  ** OH + SO2  SO4-2        (gas-phase slow reaction forms new particles )

## What is Wet Deposition of Sulfate?

- Wet deposition is the process which forms acid rain
- Occurs when clouds containing sulfate aerosols precipitates as rain
- It can be formed in rain, fog and snow
- Wet deposition is 40-80% of total deposition

## Objectives 

- The study attempts to answer two questions
- Do future changes in physical climate  affect sulfur deposition?
- Comparisons of resent day (1995) and future (2030) climate conditions and its effect on changes in distributions of wet sulfate deposition
- How will changes in future emissions (from fossil fuel burning) affect sulfur deposition?
- Comparisons of A1B and B1 scenarios under future climate conditions to the control 1995 data set

## Model Description 

- Models are used for forecasting atmospheric composition and climate conditions
- The model used is Model III which tracks 23 layers of the atmosphere
- It consist of grid boxes that are 4ox5o
- Model III incorporates the chemistry and physics of each grid box and calculates the fluxes between them
- Boundary conditions from sea surface and sea ice temperature (these measurements came from another model)
- The models can show climate change and the effect the distribution of pollutants
-  Models can also show the impact of different emission scenarios

## Future Scenarios

_**A1B Pessimistic Scenario**_
-   Rapid economic growth
-    Rapid population growth (2050      population peaks)
-    **Balance** between fossil fuels and other energy sources

_**B1 Optimistic Scenario**_
-   Rapid economic growth
-    Rapid population growth (2050      population peaks)
-  Reductions in material intensity, and the introduction of clean and resource-efficient technologies

- http://www.chooseclimate.org/jcm24dec02/doc/emit/sres.html

- The study compares two future emissions scenarios devised by the IPCC

## 1995 Control Chart

- Sulfate wet deposition
- PD control = 26 Tg S / yearEastern 2/3 of USA and Western Europe show similar rates of sulfate deposition between .9 – 3.6 (10-11 kg/m2/s)
- Highest rates of deposition are seen over southern India, SE Asia, particularly eastern China with values ranging as high as 4.5 – 7 (10-11 kg/m2/s)

## Impact of Climate Change on Sulfate Wet Deposition

- Using the A1B Scenario
- Most regions climate change has  negligible impact
- India shows reductions of ~20%
- Europe appears unchanged
- Parts of SE Asia show ~30% increase in wet deposition in the 2030 Climate

**2030 Climate  - 1995 Climate**

## Effects of Climate and Emissions on Deposition 

- A1B Scenario
- A1B 2030 climate + emissions = 37 Tg S / year
- Europe shows no net change
- USA shows moderate reductions in SO4-2 deposition
- India and SE Asia show moderate to high increases
- B1 Scenario
- B1 2030 climate+emissions = 27 Tg S /year
- Europe and the USA show a range of decrease in acid deposition of ~5-40%
- Eastern China shows similar reductions
- India continues to show increases

- 2030 A1B – 1995 Control

- 2030 B1 – 1995 Control

**Notes:**
Each of these images show the difference of the 95 control compared to the future scenarios with the 2030 climate.

## Conclusions

**The Effects of “Climate Only” study**
- Showed no impact on distribution of sulfate deposition across Europe and USA
- Climate change produced decreases in sulfate wet deposition in India (~30%),
**Effects of Climate and Emissions study**
- Combined effects of emissions and climate changes relative to the 95 Control, showed
- Decreases in sulfate wet deposition in USA for the pessimistic (A1B) scenario
- Developing regions like India, Bangladesh, and SE China showed moderate to high increases of ~30-50% in acid deposition
- The effects of climate and emission changes for the B1 scenario showed:
- A broad trend in the NH of decreasing wet deposition, in contrast to the SH which shows the opposite trend.
- Compared to the A1B scenario, greater areas of USA, Western Europe and Eastern China show broad decreases in acid deposition

## Work in Progress

- Future studies include impacts of climate change on surface concentrations of other aerosol pollutants:
- Dry Deposition of Sulfates SO4-2
- Surface level O3
- PAN
- CO
- The concentrations and distributions of these pollutants will be also be forecasted for 2030 using the A1B and B1 scenarios and the 1995 and 2030 data sets