Future Climate Change

 Future Climate Change

Introduction

Climate change is a critical issue facing our planet, caused by the increasing concentrations of greenhouse gases in the atmosphere. These emissions are a result of human activity, such as the burning of fossil fuels and deforestation. Unless these emissions are substantially reduced, greenhouse gas concentrations in the atmosphere will continue to increase. The effects of these changes are widespread and will impact many aspects of our lives, including food supply, water resources, infrastructure, ecosystems, and even our own health. In this notebook, we will explore the potential impacts of climate change on our planet, including temperature changes, changes in precipitation and storm events, and changes to ice, snowpack, and permafrost.

Factors Influencing Future Climate Change

The magnitude and rate of future climate change will primarily depend on the rate at which greenhouse gas concentrations in the atmosphere continue to increase, as well as how strongly features of the climate (e.g., temperature, precipitation, and sea level) respond to these changes. Additionally, natural influences on climate, such as volcanic activity and changes in the sun's intensity, will also play a role in future climate changes.

Long-Term Effects of Greenhouse Gas Emissions

Greenhouse gases can remain in the atmosphere for long periods, and even if we stopped increasing emissions, atmospheric greenhouse gas concentrations would continue to increase for hundreds of years. Additionally, surface air temperatures would continue to warm, as the oceans take many decades to fully respond to higher greenhouse gas concentrations. Therefore, the oceans' response to higher greenhouse gas concentrations will continue to impact climate over the next several decades to hundreds of years.

Temperature Changes

Global warming has already occurred over the last few decades, and future temperatures are expected to change further. Climate models project an increase in average global temperatures of 2◦F to 11.5◦F by 2100, depending on the level of greenhouse gas emissions and outcomes from various climate models. By 2100, global average temperature is expected to warm at least twice as much as it has during the last 100 years. Ground-level air temperatures are expected to continue to warm more rapidly over land than oceans, and some parts of the world are projected to see larger temperature increases than the global average.

Precipitation and Storm Events

Changes in precipitation and storm events are also likely to occur due to climate change. Projections show that future precipitation and storm changes will vary by season and region, with some regions experiencing less precipitation, some experiencing more precipitation, and others experiencing little or no change. The amount of rainfall during heavy precipitation events is likely to increase in most regions, while storm tracks are projected to shift poleward. Climate models project global average annual precipitation through the end of the century to increase, although changes in the amount and intensity of precipitation will vary by region. The intensity of precipitation events will likely increase on average, particularly in tropical and high-latitude regions that are also expected to experience overall increases in precipitation. The strength of winds associated with tropical storms is likely to increase, and the amount of precipitation falling in tropical storms is also likely to increase. Annual average precipitation is projected to increase in some areas and decrease in others.

Ice, Snowpack, and Permafrost

Arctic sea ice is already declining, and the area of snow cover in the Northern Hemisphere has decreased since about 1970. Permafrost temperature has increased over the last century. Over the next century, sea ice is expected to continue to decline, glaciers will continue to shrink, snow cover will continue to decrease, and permafrost will continue to thaw. These changes have the potential to impact many aspects of our lives, including water resources, transportation infrastructure, and natural ecosystems.

Conclusion

The effects of climate change are widespread and will have significant impacts on various aspects of our lives, including food supply, water resources, infrastructure, ecosystems, and human health. The increasing concentrations of greenhouse gases in the atmosphere will result in higher average global temperatures, changes in precipitation patterns, melting of ice and snow cover, rising sea levels, and increased ocean acidity. The magnitude and rate of these changes will depend on various factors, such as the rate of greenhouse gas emissions, the response of climate features to these emissions, and natural influences on climate.

Even if we were to reduce greenhouse gas emissions to zero, the atmospheric concentrations of these gases would remain elevated for hundreds of years, resulting in continued warming of surface air temperatures. Climate models predict that global temperatures are expected to increase by 2 to 11.5°F by the end of the century, depending on the level of future greenhouse gas emissions and the outcomes from various climate models. The rate of temperature increase is expected to be twice as much as it has been over the past 100 years, and ground-level air temperatures are projected to increase more rapidly over land than oceans. Some regions of the world are expected to see more significant temperature increases than the global average.

Changes in precipitation patterns and storm events are also likely to occur, with some regions experiencing more precipitation and others experiencing less. However, the exact changes are less certain than temperature changes, and projections indicate that changes will vary by region and season. The amount of rainfall in heavy precipitation events is likely to increase in most regions, and storm tracks are projected to shift poleward.

Changes in ice and snow cover are already being observed, with declining Arctic sea ice and reduced snow cover in the Northern Hemisphere. Over the next century, it is expected that sea ice will continue to decline, glaciers will continue to shrink, snow cover will decrease, and permafrost will continue to thaw. These changes will have significant impacts on ecosystems and human communities, particularly those in coastal areas.

Overall, the effects of climate change will be far-reaching and long-lasting, and it is crucial that we take immediate and sustained action to reduce greenhouse gas emissions and mitigate the impacts of climate change on our planet.

Climate Change: Earth’s Temperature is a Balancing Act

 Causes of Climate Change

Earth’s Temperature is a Balancing Act

Earth's temperature depends on the balance between energy entering and leaving the planet's system. When incoming energy from the sun is absorbed by the Earth system, Earth warms. When the sun's energy is reflected back into space, Earth avoids warming. When energy is released back into space, Earth cools.

Factors that affect Earth's energy balance

Many factors, both natural and human, can cause changes in Earth's energy balance, including:

• Changes in the greenhouse effect, which affects the amount of heat retained by Earth's atmosphere
• Variations in the sun's energy reaching Earth
• Changes in the reflectivity of Earth's atmosphere and surface

These factors have caused Earth's climate to change many times.

Natural Causes of Climate Change

Scientists have pieced together a picture of Earth's climate, dating back hundreds of thousands of years, by analyzing a number of indirect measures of climate such as ice cores, tree rings, glacier lengths, pollen remains, and ocean sediments, and by studying changes in Earth's orbit around the sun. The historical record shows that the climate system varies naturally over a wide range of time scales. In general, climate changes prior to the Industrial Revolution in the 1700s can be explained by natural causes, such as changes in solar energy, volcanic eruptions, and natural changes in greenhouse gas (GHG) concentrations.

Human Causes of Climate Change

Recent climate changes, however, cannot be explained by natural causes alone. Research indicates that natural causes are very unlikely to explain most observed warming, especially warming since the mid-20th century. Rather, human activities can very likely explain most of that warming.

The Greenhouse Effect Causes the Atmosphere to Retain Heat

When sunlight reaches Earth's surface, it can either be reflected back into space or absorbed by Earth. Once absorbed, the planet releases some of the energy back into the atmosphere as heat (also called infrared radiation). Greenhouse gases (GHGs) like water vapor (H2O), carbon dioxide (CO2), and methane (CH4) absorb energy, slowing or preventing the loss of heat to space. In this way, GHGs act like a blanket, making Earth warmer than it would otherwise be. This process is commonly known as the "greenhouse effect".

Global Warming and Climate Change

Global warming refers to the recent and ongoing rise in global average temperature near Earth's surface. It is caused mostly by increasing concentrations of greenhouse gases in the atmosphere. Global warming is causing climate patterns to change. However, global warming itself represents only one aspect of climate change. Climate change refers to any significant change in the measures of climate lasting for an extended period of time. In other words, climate change includes major changes in temperature, precipitation, or wind patterns, among other effects, that occur over several decades or longer.

The Main Greenhouse Gases

The most important GHGs directly emitted by humans include CO2, CH4, nitrous oxide (N2O), and several others.

Carbon Dioxide

Carbon dioxide (CO2) is the primary greenhouse gas that is contributing to recent climate change. CO2 is absorbed and emitted naturally as part of the carbon cycle, through animal and plant respiration, volcanic eruptions, and ocean-atmosphere exchange. Human activities, such as the burning of fossil fuels and changes in land use, release large amounts of carbon to the atmosphere, causing CO2 concentrations in the atmosphere to rise.

Atmospheric CO2 concentrations have increased by almost 40% since pre-industrial times, from approximately 280 parts per million by volume (ppmv) in the 18th century to 390 ppmv in the early 21st century.