Earth’s climate system responds to small changes in the orbit of the sun and its rotation. Small variations in the Earth’s rotation and latitudinal solar energy distribution initiated ice-age cycles, which triggered changes in CO2 concentrations. During warm periods, the ice sheets melted and reflected less sunlight to space, releasing major greenhouse gases into the atmosphere. The climate system is sensitive to small disturbances and can be amplified by reinforcing feedback processes.
Changes in global temperature
According to the IPCC’s Sixth Assessment Report, which will be published in 2021, human-made greenhouse gas emissions have warmed the planet’s climate by nearly two degrees Fahrenheit and one degree Celsius since pre-industrial times. The average global temperature is expected to increase by 1.5 degrees C or 3.5 degrees Fahrenheit within the next century. This change will affect all regions of the Earth. Here are some key effects of global warming.
The Earth’s climate has changed over the last 4.5 billion years. The reasons for these changes are multifaceted. Volcanic eruptions, variations in the Earth’s orbit, and changes in the Sun’s intensity have contributed to these changes. Other factors include the evolution of life and meteorite impacts. In the last 8,000 years, sea levels rose by more than 120 meters. During these times, warmer temperatures led to the beginning of agriculture and the development of permanent settlements and populations.
Scientists estimate that temperatures globally have increased 0.5 to 1.0 degrees Fahrenheit (0.7 to 0.6 degrees Celsius) in the last 100 years. While these changes have been significant, the rate of change has not been consistent around the world. This is evident in the U.S. map. Western regions have become warmer, while eastern regions have cooled. This trend is likely related to the presence of excessive sulfates in the air.
The oceans are the primary source of stored heat in the climate system, accounting for 90% of all global warming between the 1970s and the present. The most noticeable warming has occurred near the surface of the oceans, with the upper 75 m of water warming by 0.11degC every decade since the 1970s. Mountain glaciers are also contributing to global sea level rise, and melting has increased sharply in recent decades. The warming of the oceans will continue to result in increased temperatures.
The Earth’s wobble affects the amount of solar energy reaching the Earth’s surface, causing periods of warming and cooling. The average temperature of the planet has changed more than six degrees Celsius over the past hundred years, and this trend is expected to continue. In fact, the wobble in the Earth’s rotation causes temperatures to rise and fall. This natural cycle happens over a long period of time. The sudden change in temperatures that humans have caused only occurred recently is a result of human activity. Scientists have discovered that greenhouse gases in the atmosphere act like a blanket, trapping heat.
Impacts of human-driven greenhouse gas emissions on climate
Human activity contributes to the production of several greenhouse gases (GHGs), the most prominent of which is carbon dioxide, which accounts for about half of the global total. These emissions, which are largely associated with the burning of fossil fuels, are also responsible for the rise in temperature. Other greenhouse gases include methane and nitrous oxide, which have different warming effects but are related to poor air quality. Burning fossil fuels is the leading source of human-driven emissions of these gases, accounting for almost 80% of all human-generated emissions. Methane emissions are generated by landfills and agriculture, while nitrous oxide emissions are due to industrial processes and waste management.
Increased amounts of these gases contribute to the warming of the Earth’s atmosphere. All three gases are responsible for warming the Earth’s climate, but CO2 has the largest effect. Information about the greenhouse gases’ human-generated emissions affects climate change is found on page B3 of the report. However, it’s important to note that the warming of the Earth is the result of the accumulation of these gases, not just one.
Unless governments act now to control GHG emissions, the effects of climate change will be felt by all people around the world. But some groups will be disproportionately affected, such as low-lying island states and countries that are less developed. The Marshall Islands, for example, are regularly affected by hurricanes and floods. The heatwave of 2021 in North America and Europe made headlines, with temperatures as high as 52degC in Pakistan. Thousands of people were unable to access air conditioning or clean water, and the electricity blackouts added to their misery.
The industrial sector is one of the largest sources of human-driven emissions. It accounts for about one-fifth of global emissions and over twenty-four percent of U.S. man-made emissions. Among other sources, the industrial sector also releases nitrous oxide and fluorine-laden gases. In addition to fuel combustion and refining, transportation is responsible for 9.6 percent of the global emissions of carbon dioxide.
Impacts of ocean warming
Warming oceans cause the sea to rise, threatening the livelihood of people near coastal areas. Increasing ocean temperatures cause a thinning of sea ice shelves, with serious consequences for Earth’s climate system. Aside from the immediate threat to human life and livelihood, the warming oceans are also a danger to marine ecosystems. Coral reefs are critical for marine life, providing shelter and food. Rising ocean temperatures could also lead to devastating impacts on coastal communities and their coastal economies.
Scientists estimate that up to 1 million species live in the world’s oceans. Warmer ocean waters could lead to the mass migration of species, resulting in global homogenization of biodiversity. Warmer waters would lead to a decline in species in warmer regions, with a sudden increase in their numbers in colder regions around the poles. Ultimately, this could have a devastating impact on global aquaculture and fisheries. According to the Food and Agriculture Organization of the United Nations, fish constitute 20 percent of animal protein worldwide.
The warming ocean may also contribute to sea level rise by changing ocean circulation patterns. Warm ocean currents may slow down or even stop altogether in some parts of the world, which would affect the continents’ climate. For example, in northern Europe, the melting of sea ice may result in lower winter temperatures. And as the sea ice levels rise, the climate will change, too. So the impacts of ocean warming on earth’s climate past and future should be understood.
Ocean acidification is a result of ocean warming. Oceans are now holding a third of the carbon dioxide released by human civilization. Carbon dioxide increases the pH level of seawater, making it more acidic and more difficult for some marine organisms to build shells or skeletons. This process may ultimately change the ocean’s biodiversity and ecosystems. The consequences of ocean acidification on earth’s climate are not just obvious, but potentially disastrous.
The economic value of living oceans cannot be calculated, but it is clear that these ecosystems are essential for our survival. Changing ocean temperatures will cost us dearly. As a result, reduced tourism due to coral bleaching and the loss of reef ecosystem services may be worth up to $1 trillion per year by the year 2100. But the true cost will be felt in human security and health.
Impacts of land-based vegetation
Researchers have found that the change in land-based vegetation is a major contributor to Earth’s climate. They found that the changes are explained by changes in the surface energy balance of the planet, which correspond to conditions where TXx occurs. The current study uses four different SSPs, or Shared Socioeconomic Pathways, to analyze the impacts of different land-based vegetation scenarios on climate.
Vegetation is a primary producer in terrestrial ecosystems and plays an important role in carbon, water, and energy transfers. Furthermore, many aspects of vegetation activity mirror large-scale patterns of climate change. Therefore, studies of the response of vegetation to climate change provide the theoretical basis for ecosystem-based adaptation. However, many of these studies are still hampered by complex ecological relationships.
Greening is a key component of mitigation strategies for land-based vegetation, but it is not sufficient to prevent land-based warming. Increasing the density of vegetation can reduce the climate warming effects by at least half. Vegetation-based mitigation will not only counteract warming, but it will also enhance carbon sequestration. The biophysical effects of vegetation-based mitigation are complicated, and their relative magnitudes can vary widely. The authors note that about half of this mitigation effect is attributable to the expected increase in vegetation density. The remaining half is a result of changes in the background climate, which reduce radiative warming and enhance non-radiative cooling.
Although global warming is a concern for the future, many studies already indicate the long-term impacts of the change in land-based vegetation. For example, sea ice and permafrost thawing are two of the most likely effects. In addition, plant and animal geographic ranges are shifting and plants are blossoming earlier. The climate-based vegetation is a key contributor to the increase in sea ice.
HAPPI-Land is a project to study the impacts of land-based vegetation on climate. This research has shown that land-based vegetation can significantly differ from the HAPPI-Land scenario and add uncertainty to predictions of extreme temperatures. In fact, land-based vegetation can contribute to a substantial portion of the change in temperature extremes in low-emission scenarios (ECMWPs), which is a crucial component of future climate models.
