**Abstract**

The process of global warming over the past two centuries has become a major and challenging topic among researchers and policymakers at the international level. The process of global warming has accelerated following the increase in greenhouse gas emissions due to excessive consumption of fossil fuels after the Industrial Revolution of the eighteenth century. The growing trend of the population due to scientific advances in the field of medical sciences, rising levels of education, and health among human societies have had a tremendous impact on reducing mortality and increasing the global population. Consumerism and diversity in consumption patterns among human societies have caused more pressure on the earth's natural resources and excessive use of fossil fuels for industrial production, which has exacerbated pollution and increased greenhouse gases, especially carbon dioxide has led. Global warming can have undesirable consequences in various fields, including agriculture, water resources, plant and animal life, and biodiversity. This chapter deals with the consequences and effects of global warming on agricultural climate indicators. Finally, some agricultural adaptation strategies with these changes are presented.

**Keywords:** climate change, agriculture, global warming, green house gases

### **1. Introduction**

Today, the issue of climate change has been considered one of the most controversial problems in the world and has led to the reaction of governments and nations. Climate change is not a new issue, as in the past geological periods it has occurred frequently.

More than 35 types of greenhouse gases are produced by humans, which increases global warming. Perhaps the most important greenhouse gas is CO2, much of which is due to fossil fuel consumption during the post-industrial revolution in the eighteenth century [1]. Recently, the increase in other greenhouse gases such as (N2O), (CH4), (C.F.C) have had the same effect as carbon dioxide effects on increasing the greenhouse effect. Overall, 60% of greenhouse effects have resulted from water vapor, 26% due to carbon dioxide and other gases accounted for 14% of this contribution [2]. **Figure 1** represents the contributions of the most important long-lived greenhouse gases to the increase in global radiative forcing from the pre-industrial era to 2019.

Scientists have found a new chemical threatening the atmosphere that appears to be a long-life greenhouse gas. This chemical - Perfluorotributylamine - is the most effective radiation chemical found to date and was more effective than other chemicals regarding its possible impact on the climate [3].

Asakere quotes Landsberg (1975), climate change occurs when reflected in atmospheric rotation patterns and global and at least regional meteorological

#### **Figure 1.**

*Contributions of the most important long-lived greenhouse gases to the increase in global radiative forcing from the pre-industrial era to 2019 [3].*

processes. He called the temporary deviation that ultimately leads to the return of the previous position or the opposite position as fluctuation. Many atmospheric scientists show little passion to use the term of climate change to explain such alterations. They mainly prefer to use expressions such as variation, long-term climatic variation, climatic anomalies (deviations or anomalies), or climatic fluctuation [4].

**The climate in past geological eras:** Climate surveys in past geological periods illustrate that important climate change has occurred in the past. Important events of climate change in the past are briefly [2]:


**Figure 2** represents the relative air temperature variations (warmer and cooler periods) during the past 18,000 years. Some regions of the world experienced a cooling and other regions warming that either preceded or lagged behind the temperature variations shown in the diagram [2].

**Figure 3** represents that the average temperature variations over the Northern Hemisphere for the last 1000 years relative to the 1961 to 1990 average (zero line). The blue line represents air temperatures constructed from tree rings, corals, ice cores, and pollen. Yearly temperature data measured by thermometers are in

#### **Figure 2.**

*Relative air temperature variations (warmer and cooler periods) during the past 18,000 years. These data, which represent temperature records compiled from a variety of sources, only give an approximation of temperature changes.*

#### **Figure 3.**

*The average temperature variations over the northern hemisphere for the last 1000 years relative to the 1961 to 1990 average (zero line). (reprinted by permission of the intergovernmental panel on climate change).*

black. This reconstruction has been compared to other similar reconstructions. The area shaded orange represents where these reconstructions overlap the data by 50% or more. (Source: Adapted from Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, 2007.

#### **2. Possible causes of climate change**

The main reasons for this change can be divided into two groups, including the changes caused by natural events and humans [2]:

**Climate change caused by natural events:** Research shows that climate change occurs under the following conditions.

