M. K. Wanigasuriya AG/2008/2737 Department of crop

science Faculty of Agriculture

The free encyclopedia ‘Wikipedia’ provide us with the followings

Climate change is a significant and lasting

change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average (e.g., more or fewer extreme weather events). Climate change may be limited to a specific region or may occur across the whole Earth

•Agriculture is highly sensitive to climate variability and weather extremes, such as droughts, severe storms.

• Human activity has already changed atmospheric characteristics such as temperature, rainfall, levels of carbon dioxide (CO2) and ground level ozone.

The demand for world agriculture output will grow exponentially over coming decades due to world population growth and expanding world economies. At the same time, the agriculture sector will be impacted by changes in climate that will challenge the productivity of the world’s agriculture resources

The researchers calculated the impact of the climate trends on global crop yields. Maize production would have been about six percent higher and wheat production about four percent higher had the climate trends since 1980 not existed. The effects on rice and soybeans were lower and not statistically significant.

Recent studies indicate that increased frequency of heat stress, droughts and floods negatively affect crop yields and livestock

Climate variability and change also modify the risks of fires, pest and pathogen outbreak, negatively affecting food, fiber and forestry.

Average temperature increase Change in rainfall amount and patterns Rising atmospheric concentrations of CO2

Pollution levels such as troposphere ozone Change in climatic variability and extreme

events weed pest and pathogen

• Increasing atmospheric CO2 levels, driven by emissions from human activities

• It response for – enhance the growth of crops – yield of crop – Quality of the grain

CO2 can be one of a number of limiting factors that, when increased, can enhance crop growth.

A plant takes in atmospheric carbon dioxide (CO2) during the photosynthesis process, utilizes the carbon (C) to build the plant

Increased levels of carbon dioxide have a positive impact on plant growth such as wheat, rice and soybeans

• high N soil contents increase the relative response to elevated atmospheric CO2 concentrations

• This increase was caused by removing N limitation to plant growth through the application of N fertilizer.

• A decline in N availability may be prevented by an increase in biological N2 fixation under elevated atmospheric CO2

concentrations.

The expected rise in CO2 concentration from 390 to 550 umol by the middle of this centaury will have significant impact of crop productivity

Experiments under optimal conditions

show that doubling the atmospheric CO2 concentration increases leaf photosynthesis by 30%–50% in C3 plant species and 10%–25% in C4 species

Crop yield increase is lower than the photosynthetic response

many limiting factors such as pests, weeds, nutrients, soil water and air quality, Temperature

Elevated CO2 will modify many of the grain quality traits such as proteins , minerals (Zink and Iron) and fatty acid composition and starch properties

• Global average temperatures have risen by about 0.13 Centigrade per decade since 1950.

• It is expected to increase to about 0.2 Centigrade per decade over the next two to three decades.

India and the United States suffered very low rainfall throughout suffered sharp harvest reductions because of record temperatures and drought

In 2003 Europe record level of heat damaged most crops from the United Kingdom and France in the Western Europe through Ukraine in the East

lengthen the growing season in regions with a relatively cool spring and fall

adversely affect crops in regions where summer heat already limits production

increase soil moisture evaporation rates increase the chances of severe droughts

An increase in temperature will speed up development.

In the case of an annual crop, the duration between sowing and harvesting will shorten (for example, the duration in order to harvest corn could shorten between one and four weeks).

The shortening of such a cycle could have an adverse effect on productivity because senescence would occur sooner

The free encyclopedia ‘Wikipedia’ provide us with the followings Seaweed is a loose colloquial term encompassing macroscopic, multicultural, benthic marine algae. The term includes some members of the red, brown and green algae. Seaweeds can also be classified by use (as food, medicine, fertilizer, industrial, etc.)

Seaweed act as "trees of the ocean," providing food, shelter and habitat for many other living things.

Warming ocean waters could force hundreds of Australian seaweed species to shift southward in search of cooler waters, and eventually, force them off Australia's continental shelf, and possibly into extinction, according to a study.

Changes in seaweed communities could have dramatic effects on other living things, since seaweeds provide habitat and food

• Changes in rainfall can affect soil erosion rates and soil moisture, both of which are important for crop yields.

• The Intergovernmental Panel on Climate Change( IPCC )predicts that precipitation will increase in high latitudes, and decrease in most subtropical land regions—some by as much as about 20 percent.

• While regional precipitation will vary the number of extreme precipitation events is predicted to increase

the ozone that is a byproduct of certain human activities does become a problem at ground level

Unlike most other air pollutants, ozone is not directly emitted from any one source.

Tropospheric ozone is formed by the interaction of sunlight, particularly ultraviolet light, with hydrocarbons and nitrogen oxides,

which are emitted by automobiles, gasoline vapors, fossil fuel power plants, and certain other industries

While stratospheric ozone shields us from ultraviolet radiation,

in the troposphere this irritating, reactive molecule damages forests and crops and other materials; and injures or destroys living tissue.

Ozone affects plants in several ways. High concentrations of ozone cause

plants to close their stomata. These are the cells on the underside of the plant that allow carbon dioxide and water to diffuse into the plant tissue. This slows down photosynthesis and plant growth.

Ozone may also enter the plants through the stomata and directly damage internal cells.

• increasing ozone concentrations in future decades, with or without climate change, will negatively impact plant production, possibly increasing exposure to pest damage

• Change in climatic variability and extreme events: Changes in the frequency and severity of heat waves, drought, floods and hurricanes, remain a key uncertainty in future climate change.

• Such changes are anticipated by global climate models, but regional changes and the potential affects on agriculture are more difficult to forecast.

• Most of the increase in agricultural production over the last century is the result of yield increases rather than agricultural land area expansion.

• However, due to the world’s rapidly growing demand for food and the negative yield impact of climate change on food production, there will be great pressure to expand the world’s agricultural land area.

• Increased investments in agricultural research in the world is needed to meet the challenge of world crop production.

• this investments must be combined with programs to substantially reduce greenhouse gas emissions.

• Use renewable energy sources • Develop home garden concept in the

world• Carbon treading

http://en.wikipedia.org/wiki/Climate_change_nd_agriculture

http://www.ucar.edu/learn http://www.oecd.org/document http://www.epa.gov/climatechange/

effects/agriculture.html Wynne Parry, Live Science Senior Writer

Date: 27 October 2011 Time: 12:01 PM E International conference on the impact of

climate change on agriculture December ,20,2011 (ICICCA 2011)

Crop and pasture response to climate change

Francesco N. Tubiello ,Jean-François Soussana,

S. Mark Howden