1. Climate Change, and Public Health: the Botanical Perspective.
Lewis H. Ziska, USDA-ARS
Thanks to:
Linda Ford, MD American Lung Association, Omaha, NE
James Straka, PhD, Macalester College, St. Paul, MN
David Frenz, MD, the Bethesda Clinic, St. Paul, MN
Jonathan Patz, MD Johns Hopkins, Baltimore, MD
Dennis Gebhard, Multidata Inc., St. Paul, MN
Paul Epstein, MD, Harvard, Boston, MA
Maryland Department of Natural Resources, February 19, 2009

2. Atmospheric CO2
So what if CO2 goes up?

3. I. An indirect effect of rising carbon dioxide: warmer temperatures.
Gas %
Nitrogen (N2)
78.1
Oxygen (O2)
20.1
Argon (Ar)
0.93
Carbon Dioxide (CO2)
0.04 up to 0.100
Water (H2O)
0.05 to 1.00
Carbon dioxide absorbs heat leaving the earth’s atmosphere. The more you put in the atmosphere, the more heat is trapped. This is a simple physical explanation of global warming.
No H2O and CO2? Surface temperature would be –18oC. With H2O and CO2? Surface temperature is 15oC.

4. H2O vs. CO2 Poles Winter latitude Deserts Equator
If water vapor is high, it will be the dominant warming gas….little effect of CO2
If water vapor is low, adding CO2 will increase the surface temperature.

5. Greenland is melting
Greenland ice loss rate doubled in last 10 yrs 5

6. CO2, warming and public health.
Changes in range of insect or rodent borne diseases.
Changes in water or seafood borne diseases.
Increasing ground-level ozone, and respiratory ailments.
Contamination of drinking water due to excessive flooding.
Heat-related deaths / fewer cold related.

7. So what if CO2 goes up?, Part II, direct impacts
Carbon dioxide is the source of carbon for photosynthesis, and consequently for 99% of all life.
CO2
Food, Glorious
Food!
Nutrients, H2O
CO2 + H2O + light  O2 + organic C + chemical energy

8. Plants are Important. Michael Crichton, Page 86, “Jurassic Park”
Plants are necessary for the flow of energy and carbon through
ecosystems. 90% of all living matter consists of plant life.
With the exception of a few subterranean organisms, if plants
did not exist, life would not exist.
Plant growth however is dependent on four physical inputs.
Any perturbation in these inputs will alter all living systems.
“People who imagined that life on earth consisted of animals moving against a green background, seriously misunderstood what they were seeing. That green background was busily alive. Plants grew, moved, twisted and turned, fighting for [resources]; and they interacted continuously with animals—discouraging some with bark and thorns, poisoning others, and feeding still others with pollen and seeds. It was a complex, dynamic process…one which most people didn’t understand. “
Michael Crichton, Page 86, “Jurassic Park”

9. But isn’t more plant growth desirable?
“We are living in an increasingly lush environment of plants and animals as a result of the carbon dioxide increase. This is a wonderful and unexpected gift from the industrial revolution.” WSJ

10. CO2 is a VERY smart molecule.
Green is not always good.

11. All life will be affected not only by temperature, but by the increase in carbon dioxide of and by itself. What are the implications for Weed Biology? Specifically:
Crops and weeds
Invasive weeds
Public Health.

12. How can plants affect public health? Some direct effects:
Allergies / Asthma:
Contact dermatitis:
Poison/Toxicology:

13. 1. CO2, plants and allergies
Principle Fall Allergen
~35 million sufferers
Common ragweed.

14. Determining Ragweed Pollen Production
Sampling pollen from ragweed catkins.

15. Response of common ragweed to CO2
g plant-1
Pollen Production
280 ppm g
370 ppm g*
600 ppm g*
Antigen Amb a1 ELISA / mg protein
280 ppm
370 ppm 5290
600 ppm 8180*
Chamber Study, USDA
Functional Plant Biology 27:
Functional Plant Biology 32:
280
370
600

16. Ragweed in real life
All this is “blue-sky” hypothetical &*^$%# anyway. It won’t
happen in real-life, and even if it does, temperature and carbon
dioxide effects are a long ways away.
10,000 feet on a mountaintop in Hawaii.
Mauna Loa, “Official” CO2 data.

17. Is the rise in CO2 the same everywhere?
Change in average day-time CO2 concentration (ppm) from downtown Baltimore to an organic (rural) farm.
455.5
402.2
386.2

18. Is the increase in temperature the same?
20.7
19.1
18.6
Change in average daily temperature (oC) from downtown Baltimore to an organic (rural) farm (2002).

19. Urbanization and climate change.
Are these differences consistent?
CO2 differences
August, 2004
What about other meteorological variables?
8-h daytime ozone.
2004 season
Overall: Urban-induced increases in carbon dioxide, air
temperature and growing season are consistent with most IPCC
near-term scenarios. With the exception of N deposition, other
variables did not differ consistency, but N low relative to soil N.

20. And if it isn’t…Can we study the effects of climate change NOW?
Placing four 2x2 m2 plots
Near downtown Baltimore.
Use same soil and seed bank
in suburban and rural locations.

21. Got ragweed?
2006
Urban locale had longer growing season (milder winter), warmer
temperatures, and more carbon dioxide.

22. Allergenic pollen producers, Western Weeds:
Season: April through November
Ragweed (A. atemissiifolia) Pigweed (Amaranthus retroflexus)
Giant Sagebrush (Artemisia tridentata) English plantain (Plantago lanceolata)
Russian thistle (Salsola kali) Fireweed (Kochia scoparia)
Marsh elder (Iva species) Cocklebur (Xanthium strumarium, X. spinosa)
Yellow Dock (Rumex crispus) Lambsquarter (Chenopodia album)
Allergenic pollen producers, Mid-Western Weeds:
Season: May through October
Ragweed (A. atemissiifolia) Pigweed (Amaranthus retroflexus)
Giant Ragweed (A. trifida) English plantain (Plantago lanceolata)
Russian thistle (Salsola kali) Fireweed (Kochia scoparia)
Marsh elder (Iva species) Cocklebur (Xanthium strumarium, X. spinosa)
Lambsquarter (Chenopodia album)
Allergenic pollen producers, Southern Weeds:
Season: April through November
Ragweed (A. atemissiifolia) Pigweed (Amaranthus retroflexus)
Giant Sagebrush (Artemisia tridentata) English plantain (Plantago lanceolata)
Marsh elder (Iva species) Cocklebur (Xanthium strumarium, X. spinosa)
Yellow Dock (Rumex crispus) Lambsquarter (Chenopodia album)
Allergenic pollen producers, Northeast Weeds:
Season: May through September
Ragweed (A. atemissiifolia) English plantain (Plantago lanceolata)
Giant Ragweed (A trifida) Russian thistle (Salsola kali)
Marsh elder (Iva species) Cocklebur (Xanthium strumarium, X. spinosa)
Pigweed (A. retroflexus) Lambsquarter (Chenopodia album)
Mugwort (Artemisia vulgaris)

23. Fungal decomposition of plants.
Alternaria alternata has been associated with a number of respiratory problems such as rhinitis, asthma, allergic dermatitis and allergic sinusitis. The spores are the cause of the allergic reactions.
For timothy grass grown from ppm CO2, rising
carbon dioxide levels results in reduced leaf N levels.
Initial data suggest that increased C:N ratios could
increase the rate of sporulation.

24. 2. CO2, plants and contact dermatitis
Can rising CO2 alter plant based dermatitis?

25. The Duke University FACE Site: State of the Art.

26. Poison ivy at Duke Face ring.

27. Poison ivy plants grow faster at elevated CO2

28. Poison ivy allergenicity
Ambient Elevated
Duke University, USDA study, PNAS 103:

29. 3. CO2, plants and poison
Castor bean (Ricinus communis), produces ricin, one of the deadliest
poisons known to man. Increasing CO2 by 300 ppm results in a 34%
increase in photosynthesis (Grimer and Komor 1999).
Vanaja et al. (2008) reports large response to rising CO2.

30. How can plants affect public health? Some indirect effects:
Food and Nutrition.
Medicines / Narcotics.
Disease vector biology.
Pesticide use.

31. CO2 and human nutrition.
% Flour protein from wheat lines released during the 20th century.
Recent cooperative work with NIH indicates an increase in omega-3-fatty
acids in mung bean with rising CO2.

32. Rice and temperature Temperature / Flowering
-There is already evidence that there has been a trend for an increase in heavy precipitation events in our region.
Rice and temperature

33. Water and food security

34. Agriculture and water Rice production
Today, approximately 230,000 people were added to the population. Three cereals, rice, wheat and corn feed 50% of that population. These cereals in turn are heavily dependent on irrigation.
~80% of freshwater is used in irrigation.
How will we maintain food supply with less water?
Rice production

35. The “Big Three” at present.
Rice
1980s: 3.1% per year
1990s: 1.4% per year
2000s: 0.8% per year
Wheat
1980s: 2.9% per year
1990s: 0.9% per year
2000s: 0.4% per year

36. Only maize has kept pace with population.
1980s: 2.2% per year
1990s: 2.5% per year
2000s: 3.5% per year
Energy Independence?
Maize is a heavy user of nitrogen fertilizer. This comes from
natural gas (Haber process, N2NH4NO3).
Russia: 47,570 billion ft3 Iran: 26,370 billion ft U.S.A.: 5,600

37. 2a. CO2, plants and medicine
Approximately 15% of all current pharmaceuticals in developed countries are
derived solely from plants (85% in undeveloped countries).

38. Alkaloids derived from plants
Cocaine
Atropine
Caffeine
Nicotine
Codeine
Morphine
Scopolamine
Thebaine

39. Atropine and scopolamine

40. 2b. CO2, plants and narcotics.
Effects unknown
Growth increases.
Anecdotal evidence

41. Papaver setigerum DC. (Wild poppy)
Quantify growth and alkaloid production to carbon dioxide
300 ppm ~1950
400 ppm Current
500 ppm ~2050
600 ppm ~2090

42. P. setigerum is sensitive to even small
(100 ppm) increases in carbon dioxide.
Greatest relative stimulation has occurred
with recent (last few decades) CO2 increase.

43. Averages P-value
Variable CO2 Effect
____________________________________________________________
Capsule No ***
Capsule Wt. (g) ***
Latex (mg) ***
Morphine (%)
Concentration of other alkaloids did not increase with increasing CO2.

44. 3-4 x increase in alkaloid production in wild poppy with recent and
projected CO2 increases. Accepted in Climatic Change

45. Nicotine production Nicotine Concentration 294 ppm 4.7 µg g-1

46. 3. CO2, plants and disease vectors plants are not vectors per se, but:
Hanta virus
Nectar & pollen
CO2 / temperature

47. 4. CO2, plants and pesticide usage.
Why can’t we just control these weeds?
Ambient CO2
Future CO2
As carbon dioxide increases, glyphosate efficacy is reduced

48. Canada thistle: Best of the worst.
We are not clear why invasives would show a strong response to carbon dioxide, there may be a number of mechanistic explanations. However, in the case of Canada thistle, below ground production (root biomass) appears to be a strong responsive sink when additional carbon dioxide is given. In this experiment, the ratio of elevated to ambient represents the growth of shoots (aboveground) and roots (below-ground) biomass at current and current +250 ppm CO2.
3 years of field trials at +250 ppm above ambient.

49. A synopsis of CO2 impacts on herbicide efficacy
Efficacy is reduced in a number of
studies. The basis for the reduction is
not entirely known. However, if more
pesticides are needed to kill weeds, then
more trace chemicals are likely in the
environment.
Change in growth rate (g dry matter per day) for agronomic and invasive weeds when sprayed at recommended rates of herbicide at either: (A) current CO2 or (B) future CO2 levels ( ppm). All growth rates less than 0.1 resulted in plant death. Herbicide was glyphosate in all cases except Canada thistle1, which was sprayed with glufosinate. Overall, these data indicate a greater resistance to chemical control in weedy species as a function of rising atmospheric carbon dioxide. The basis for a CO2 induced reduction in herbicide efficacy is not entirely clear. In the case of Canada thistle, we believe it is related to CO2 induced increases in root growth relative to shoot growth (see slide 23), and a subsequent dilution of the herbicide. Weed control could, presumably still be achieved by increasing the concentration of the herbicide, or the frequency of spraying, but this would carry as yet unknown economic or environmental costs.

50. Climate change, plants and public health
Direct Effects
Allergies
Contact dermatitis
Toxicology
Indirect Effects
Nutrition
Medicine
Spread of disease vectors
Increased pesticide use.

51. What is USDA doing?
In the last 6 years have lost one full time scientist, and two three technicians.
Budget cut every year for the last 6 years. The new farm bill has no money for studying climate change and agriculture. No stimulus funding.
National Program 204, Global warming and agriculture was eliminated in May of (although some work may continue)