**1. Introduction**

The change in climate have impacted the grassland in many ways. Grassland have the capability to buffer climate variability. They provide many other services to the ecosystem as well. The change in earth's energy budget calls for innovative methods to manage the loss of grassland. Understanding the importance of the presence of grassland, the need to manage loss and be economically efficient is crucial as well.

Atmospheric warming and climate change have the potential for significant effects on agriculture systems and their productivity. Crops and forage systems have display significant vulnerability as the change in temperature and precipitation will then impact cultivation, sowing, growth and utilisation [1]. Farmers will then have to innovate and have other management methods to counter the effects of climate change.

Climate variability have caused frequent droughts. This have impacted the grassland by increasing plant mortality and limiting the geographic distribution of plant species, accelerating grassland degradation [2]. In addition to the observable change, there are other biotic and abiotic factors that will be affected as well. The microorganisms that live in the soil biota changes. The biodiversity may decrease and alien species may increase. With the change in biodiversity in grassland, novel diseases in plant may arise. Grassland diseases are a major part of grassland management. To understand the underlying physiology of pathogens and mode of

transmission will be crucial, as intercepting at the point of weakness of pathogen's lifecycle can reduce damages to vegetation and other costs for management [3].

Different type of grasslands across the globe will have different management requirements as the difference in pathogens differ as the environmental factors differs. The imbalance of Earth's energy budget will further complicate the understanding and requirements for grassland management. Therefore, this chapter aims to cover and understand how did climate change impact the components that cause plant pathogens to continue to cause damage to grassland. In addition, the chapter covers the common types of grassland diseases that have been a recurring problem in various grasslands and its causative agents.

## **2. Earth's energy budget**

Energy cannot be created nor destroyed. Earth will require solar energy in order for the basis of life to continue. This can be evidently observed by plants requiring sunlight for photosynthesis to occur and to produce oxygen for living organisms. Earth would freeze without sunlight. The ideal balance of Earth' energy budget can be explained with the guidance of the diagram below.

In summary, the incoming solar energy is being used, reflected and radiated back to space. To achieve the ideal earth's energy budget, the incoming solar energy will be equal to the outgoing solar energy (which includes energy that have been reflected back into space).

The earth's energy is constantly changing as the energy flows through the system. The changes in earth' energy balance have been contributed by the components human activities. This causes changes to the composition of the atmospheric layers. As such, this could lead to the increased absorption of radiation or decreased absorption of radiation by reflecting those energy back into space as there is high albedo in the atmospheric layer. Albedo is an elaborate word that has a simple physical concept. Lighter surfaces on earth reflects more heat than dark surfaces. Earth's energy budget in the past was balanced by the long wavelength that is being absorbed and the short wavelength that is being reflected back into the solar system. The reflection of short waves energy could be emitted by earth's surfaces, clouds, atmosphere, conduction and/or convections and, evapotranspiration. With the imbalance of absorption and reflection it could cause a positive energy imbalance, Earth system is said to be gaining energy causing global warming. With the continuous gain in energy, the albedo in earth would decrease as the ice caps and snow starts melting.

Global warming increases not only the global temperature. The concentration levels of greenhouse gases and of those gases increase, carbon dioxide is of interest to a lot of scientist. The increase in carbon dioxide have been contributed by human activities such as deforestation and burning of fossil fuels (just some to name). The five carbon pools that will cycle the concentration of carbon in the Earth were lithosphere, oceans, soil organic matter, atmosphere and biosphere. Oceans are the biggest carbon pool in the Earth. However, deforestation has contributed to the global temperature rise as deforestation will cause a decreased in absorption of carbon dioxide. With the increase in carbon dioxide in the atmosphere have caused sun's radiation is being reflected back to earth rather than back into space. Hence, as the Earth loss the ability to release energy, the global temperature increase. Apart from carbon dioxide, the increase in concentration for other atmospheric gases will allow different wavelength of light to pass through.

Thus, greater the amount of atmospheric gases that absorb thermal infrared radiation from the Earth's surface, the greater the proportion of radiation emitted *Earth's Energy Budget Impact on Grassland Diseases DOI: http://dx.doi.org/10.5772/intechopen.99971*

from the atmosphere towards the Earth's surface [4]. This would then result in the Earth's surface being less negative. More energy is then available for sensible and latent heat flux at the surface. Thus, the increase in air temperature.

The change in earth's energy budget does not impact solely on the plants in Grassland. It would also impact those that are living in the grassland. The impact of global warming stresses the ecosystems through several changes that could already be experienced: rise in global temperature, water shortages, drought and intense storm damage. In addition to those that have been experiences, salt invasion is a rising problem. The influx of salt into the soil and water can change the ionic concentration of an area. The sudden change in soil environment will give little time for underground organisms to adapt.
