Understanding the Current State of Climate Change
Climate change isn’t just a buzzword; it’s a reality we’re living through. Present-day climate change includes both global warming and its wider effects on Earth’s climate system, driven primarily by human activities such as burning fossil fuels since the Industrial Revolution. This means that every time you turn on your heater or drive to work, you’re contributing to this complex issue. But how did we get here?
The Evolution of Climate Change Awareness
In the 1980s, terms like ‘global warming’ and ‘climate change’ started becoming more common, often used interchangeably. Back then, it was unclear whether human impacts on climate were stronger than natural cooling effects from airborne particulates. Now, we know that human activities have significantly increased greenhouse gas emissions, leading to a 50% increase in rising temperatures since the pre-industrial era.
The Impact of Climate Change
The effects of climate change are profound and far-reaching. They threaten people with increased flooding, extreme heat, food and water scarcity, disease, economic loss, human migration, and conflict. In 2024, the warmest year on record, temperatures have risen by about +1.60 °C since regular tracking began in 1850.
Limiting Warming to Safe Levels
To limit warming to 2°C, we need to halve emissions by 2030 and achieve net-zero emissions by 2050. Fossil fuel use can be phased out through energy conservation and switching to carbon-free sources like wind, solar, hydro, and nuclear power. Cleanly generated electricity can replace fossil fuels for powering transportation, heating buildings, and running industrial processes.
Historical Climate Cycles
Over the last few million years, Earth’s climate cycled through ice ages with temperatures varying between periods of warming and cooling. The most recent glacial maximum 20,000 years ago was some 5-7°C colder than today. Temperatures stabilized around 11,700 years ago and have been increasing since the Industrial Revolution.
Observations Reinforce Warming Trends
Multiple independent datasets show worldwide increases in surface temperature at a rate of around 0.2 °C per decade. The 2014–2023 decade warmed to an average 1.19 °C compared to the pre-industrial baseline. Internal climate variability processes can cause year-to-year variations, but long-term warming trends are detected by averaging over 20 years.
Regional Variations in Warming
Different regions warm at different rates, independent of where greenhouse gases are emitted. The land regions have warmed almost twice as fast as the global average since the pre-industrial period. The Northern Hemisphere and North Pole have warmed faster than the South Pole and Southern Hemisphere. Arctic surface temperatures are increasing three to four times faster than in the rest of the world.
Future Projections
The World Meteorological Organization estimates a 50% chance of the five-year average global temperature exceeding +1°C in the near future. IPCC expects +1.5 °C in early 2030s. Global warming projections show that by 2100, under low emissions, temperatures could rise between 1.0–1.8 °C; intermediate emissions could result in a 2.1–3.5 °C increase; and high emissions could lead to a 3.3–5.7 °C increase.
Causes of Recent Global Temperature Rise
The recent global temperature rise is caused by natural climate cycles, external forcings, and human contribution, including greenhouse gases. Greenhouse gases work by allowing sunlight to pass through the atmosphere but absorbing heat and slowing its escape.
Land Surface Changes and Deforestation
Around 30% of land area is unusable, 26% is forest, and 10% is shrubland. Deforestation accounts for 27% of global warming, with forests not being replaced by new trees releasing CO2. Local vegetation cover impacts albedo and evaporation rates, with deforestation modifying chemical compound release and wind patterns.
Aerosols and Their Effects
Aerosols affect climate on a large scale by scattering and absorbing solar radiation. Aerosols declined since 1990, reducing their masking of greenhouse gas warming effects. However, black carbon in soot can contribute to global warming by increasing sunlight absorption and melting sea ice.
Feedback Processes
The climate system’s response to an initial forcing is shaped by feedbacks, which either amplify or dampen the change. The main reinforcing feedbacks are water-vapour feedback, ice-albedo feedback, and cloud effects, while radiative cooling is the primary balancing mechanism.
Environmental Effects of Climate Change
The environmental effects of climate change are broad and far-reaching, affecting oceans, ice, and weather. Since the 1950s, droughts and heat waves have appeared simultaneously with increasing frequency. Extremely wet or dry events within the monsoon period have increased in India and East Asia.
Impact on Oceans
Global sea level is rising as a consequence of thermal expansion and the melting of glaciers and ice sheets. Climate change has led to decades of shrinking and thinning of the Arctic sea ice. Higher atmospheric CO2 concentrations cause more CO2 to dissolve in the oceans, making them more acidic.
Impact on Ecosystems
Climate change has driven many species poleward and towards higher altitudes, global greening, heatwaves and drought reducing ecosystem productivity, woody plant encroachment affecting up to 500 million hectares globally, and expansion of drier climate zones.
Impact on Humans
The impact on humans is severe. Temperature extremes lead to increased illness and death. Climate change increases extreme weather events, affecting transmission of infectious diseases like dengue fever and malaria. 14.5 million more deaths are expected due to climate change by 2050.
Economic Impacts
Total crop yields have decreased due to climate change. Fisheries have been negatively affected. Agricultural productivity has been positively affected in some high-latitude areas, while mid- and low-latitude areas have been negatively affected. An increase in drought could cause 3.2 million deaths from malnutrition by 2050 and stunting in children.
Adaptation to Climate Change
Adaptation to climate change is essential without additional mitigation, but more transformative adaptation requires significant investment and poses a risk if not adequately funded. Adaptation to sea level rise involves avoiding at-risk areas, learning to live with flooding, and building flood controls, or managing retreat when necessary.
Mitigation Strategies
Mitigating climate change requires reducing greenhouse gas emissions and removing carbon dioxide from the atmosphere. The goal is to limit global warming to less than 1.5°C by 2050 or 2°C by 2070, requiring far-reaching systemic changes in energy, land use, cities, transport, buildings, and industry.
Renewable Energy
Renewables represented 86% of all new electricity generation installed in 2023. Clean energy policies are needed for a rapid transition from fossil fuels to renewables by 2050. Renewable energy would dominate electricity generation, rising to 85% or more by 2050.
Adaptation and Mitigation Synergies
There are synergies between adaptation and mitigation, such as increased food productivity, but trade-offs, like the energy demand from air conditioning or the urban heat island effect. Countries most vulnerable to climate change have contributed less to global emissions, raising questions about justice and fairness.
International Climate Agreements
The Montreal Protocol has had benefits for climate change mitigation by banning ozone-depleting gases. Banning these gases may have avoided a temperature rise of 0.5°C-1.0°C and additional warming. The Kigali Amendment committed to reducing hydrofluorocarbons, which are potent greenhouse gases.
Public Debate on Climate Change
The public debate about climate change has been influenced by denial and misinformation originating from fossil fuel companies, industry groups, conservative think tanks, and contrarian scientists. Climate change came to international public attention in the late 1980s due to media coverage.
Climate Movement
The climate movement includes protests, fossil fuel divestment, lawsuits, and other activities demanding action from political leaders to prevent climate change. Prominent demonstrations include the School Strike for Climate, initiated by Swedish activist Greta Thunberg in 2018, and mass civil disobedience actions by groups like Extinction Rebellion.
Historical Discoveries
Historically, scientists such as Alexander von Humboldt and Joseph Fourier made early discoveries about climate change, including the greenhouse effect and its role in warming the planet. In 1856 Eunice Newton Foote demonstrated that water vapour and CO2 increase the warming effect of sunlight on air.
Scientific Consensus
By 2019, there was a near-complete scientific consensus that climate change is caused by humans, with agreement exceeding 99%.
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This page is based on the article Climate change published in Wikipedia (retrieved on February 5, 2025) and was automatically summarized using artificial intelligence.