Question

The scientific consensus regarding global climate change is that these changes are... A. Caused by natural, Earth-based phenomena such as volcanoes B. Poorly understood and no scientific conclusions can be made at this time C. Primarily caused by human activities D. Caused by eccentricity in Earth's orbit and by changes in solar intensity E. No greater or different than changes seen in the medieval times

Short answer

C. Primarily caused by human activities

Step-by-step solution

Understand the question

The question is about understanding the scientific consensus regarding global climate change. The term 'scientific consensus' refers to the general agreement among scientists based on a large body of evidence.

Evaluate each option

Examine each provided option to determine its accuracy based on current scientific understanding: A. Caused by natural, Earth-based phenomena such as volcanoes. B. Poorly understood and no scientific conclusions can be made at this time. C. Primarily caused by human activities. D. Caused by eccentricity in Earth's orbit and by changes in solar intensity. E. No greater or different than changes seen in the medieval times.

Identify the consensus

Scientific research and major scientific organizations have concluded that the primary cause of recent global climate change is human activities, particularly the emission of greenhouse gases from burning fossil fuels and deforestation. This rules out choices A, B, D, and E.

Select the correct answer

Based on the evaluation, the option that aligns with the scientific consensus is: C. Primarily caused by human activities.

Key concepts

Human Activities

Human activities have significantly impacted the Earth's climate, primarily through the emission of greenhouse gases. These activities include burning fossil fuels, such as coal, oil, and natural gas. When we burn these fuels for energy, it releases carbon dioxide (CO2) into the atmosphere. Another major activity is deforestation. Trees naturally absorb CO2, so when they are cut down and burned, the stored CO2 is released. Additionally, industrial processes and agricultural practices also produce other greenhouse gases like methane (CH4) and nitrous oxide (N2O).
Some common sources of human activities that contribute to global warming include:

• Transportation, especially cars, trucks, and planes that use fossil fuels
• Electricity and heat production from coal, oil, and natural gas
• Industries that produce chemicals, cement, and steel
• Agricultural activities, particularly livestock farming which produces methane
• Land use changes, such as deforestation for farming or urban development

Understanding these human activities helps us recognize the ways we can reduce greenhouse gas emissions and combat global warming.

Greenhouse Gases

Greenhouse gases (GHGs) are compounds in Earth's atmosphere that trap heat. This process is commonly known as the greenhouse effect. When the Sun's energy reaches the Earth, some of it is reflected back to space, and the rest is absorbed, warming the planet. Earth then emits heat in the form of infrared radiation, which greenhouse gases trap, preventing it from escaping into space.
Important greenhouse gases include:

• Carbon dioxide (CO2): The most significant GHG emitted by human activities, especially from burning fossil fuels and deforestation.
• Methane (CH4): Released during the production and transport of coal, oil, and natural gas, as well as through livestock and other agricultural practices.
• Nitrous oxide (N2O): Emitted from agricultural and industrial activities, as well as during combustion of fossil fuels and solid waste.
• Fluorinated gases: These are synthetic gases used in various industrial applications. Although present in smaller quantities, they are potent GHGs with a high global warming potential.

The increased concentration of these gases due to human activities intensifies the greenhouse effect, leading to global warming. Therefore, reducing greenhouse gas emissions is key to mitigating climate change and its impacts.

Global Warming

Global warming refers to the long-term rise in the average temperature of the Earth's climate system. This phenomenon is closely linked to an increase in greenhouse gas concentrations resulting from human activities.
The consequences of global warming are far-reaching and can include:

• Rising sea levels due to the melting of polar ice caps and glaciers
• More frequent and severe weather events such as hurricanes, heatwaves, and heavy rainfall
• Changes in precipitation patterns, leading to droughts in some regions and floods in others
• Ocean acidification caused by increased CO2 levels, which can harm marine life
• Disruptions to ecosystems and biodiversity, with some species unable to adapt quickly enough to the changing climate

Global warming not only affects natural environments but also has significant impacts on human societies, such as food security, health, and economies. Addressing global warming requires global cooperation to reduce greenhouse gas emissions, transition to renewable energy sources, and implement sustainable practices. By understanding the role of human activities and the dynamics of greenhouse gases, we can take informed actions to mitigate these changes and protect our planet for future generations.