Encyclopedia

Climate change refers to long-term shifts in global temperatures and weather patterns, primarily caused by human activities since the 1800s.

The greenhouse effect is a natural process where gases in Earth's atmosphere trap heat, keeping our planet warm enough to sustain life.

Carbon dioxide (CO2) is the primary greenhouse gas emitted through human activities, accounting for about 76% of global emissions.

Methane is 80 times more potent than CO2 at trapping heat over a 20-year period, though it stays in the atmosphere for less time.

The Industrial Revolution, beginning around 1760, marked the start of significant human-caused greenhouse gas emissions.

Pre-industrial CO2 levels were around 280 parts per million (ppm). Today, they exceed 420 ppm - a 50% increase.

The last time CO2 levels were this high was over 3 million years ago, during the Pliocene epoch.

Climate and weather are different: weather is short-term atmospheric conditions, while climate is the average weather over 30+ years.

97% of actively publishing climate scientists agree that human activities are causing global warming.

The Paris Agreement aims to limit global warming to 1.5C above pre-industrial levels to prevent the worst climate impacts.

The 10 warmest years on record have all occurred since 2010, with 2023 being the hottest year ever recorded.

July 2023 was the hottest month in recorded human history, with global temperatures 1.5C above pre-industrial levels.

The Arctic is warming nearly 4 times faster than the global average, a phenomenon known as Arctic amplification.

Nighttime temperatures are rising faster than daytime temperatures, affecting how ecosystems and humans recover from heat.

Land surfaces are warming faster than oceans, with some regions experiencing warming of 2-3C above pre-industrial levels.

Each decade since 1980 has been warmer than the previous one, continuing an unbroken warming trend.

Without action, global temperatures could rise by 2.5-4.5C by 2100, with catastrophic consequences.

A 2C rise would expose 420 million more people to extreme heatwaves compared to a 1.5C rise.

The temperature difference between now and the last ice age is only about 4-7C, showing how sensitive Earth's climate is.

Arctic sea ice has declined by about 13% per decade since satellite records began in 1979.

The Greenland ice sheet is losing approximately 270 billion tons of ice per year, contributing to sea level rise.

Antarctica is losing ice 6 times faster today than it was in the 1990s.

Sea levels are currently rising at about 3.7 mm per year, up from 1.4 mm per year in the early 20th century.

If all of Greenland's ice melted, global sea levels would rise by about 7.4 meters (24 feet).

If the Antarctic ice sheet melted completely, sea levels would rise by about 58 meters (190 feet).

Ocean temperatures have increased by about 0.88C since 1900, affecting marine life worldwide.

The ocean absorbs about 90% of the excess heat trapped by greenhouse gases.

Glaciers around the world are retreating, with some losing more than 30% of their mass since 1980.

The ocean has become 30% more acidic since the Industrial Revolution due to absorbing excess CO2.

Permafrost (frozen ground) in the Arctic contains twice as much carbon as the atmosphere.

As permafrost thaws, it releases methane and CO2, creating a dangerous feedback loop.

By 2100, sea levels could rise between 0.3 to 1.1 meters, depending on emission scenarios.

About 680 million people live in low-lying coastal zones threatened by sea level rise.

Climate change has made heatwaves 5 times more likely than they would be without human influence.

The number of weather-related disasters has increased five-fold over the past 50 years.

Hurricanes are becoming more intense, with a higher proportion reaching Category 4 or 5 strength.

Wildfires have increased in frequency and intensity, with fire seasons now 78 days longer on average.

Droughts are becoming longer and more severe, affecting water supplies and agriculture worldwide.

Flash floods have become 3 times more common globally compared to the 1980s.

The economic cost of weather disasters has increased sevenfold since the 1970s.

Tornadoes in the US are shifting eastward and occurring in larger clusters.

Winter storms are becoming more intense as the contrast between cold Arctic air and warming temperatures increases.

About 1 million species face extinction due to climate change and other human activities.

Coral reefs could decline by 70-90% with 1.5C of warming, and virtually disappear at 2C.

Species are moving toward the poles at an average rate of 17 km per decade to escape rising temperatures.

Spring is arriving earlier, with many plants blooming 2-3 weeks earlier than 50 years ago.

Polar bear populations could decline by 30% by 2050 as Arctic sea ice disappears.

Bird migration patterns are shifting, with some species arriving earlier or not migrating at all.

Insect populations have declined by 45% in some regions, partly due to climate change.

Forests are dying at increasing rates from droughts, heat stress, and pest outbreaks linked to warming.

Ocean "dead zones" with low oxygen have quadrupled since 1950 due to warming and pollution.

The Amazon rainforest is approaching a "tipping point" where it could transform into savanna.

Up to 50% of species in biodiversity hotspots could face extinction with 3C of warming.

Phytoplankton, which produce 50% of Earth's oxygen, are declining due to ocean warming.

Alpine ecosystems are being squeezed as species move uphill, with nowhere left to go.

Fish populations are shifting toward cooler waters, disrupting traditional fishing communities.

Deforestation and land use changes contribute about 11% of global emissions.

Agriculture is responsible for about 10-12% of emissions, primarily from livestock and rice cultivation.

The energy sector is the largest emitter, accounting for about 73% of total greenhouse gas emissions.

Transportation contributes about 16% of global emissions, with road vehicles being the biggest source.

Industrial processes and manufacturing account for about 21% of global emissions.

Buildings (heating, cooling, electricity) contribute about 18% of energy-related emissions.

China is currently the world's largest emitter (27%), followed by the US (15%) and the EU (10%).

Historically, the US has emitted more CO2 than any other country (about 25% of cumulative emissions).

The richest 10% of the global population produces about 50% of all emissions.

A single long-haul flight can generate more emissions than an average person in many countries produces in a year.

Livestock produce about 14.5% of global emissions, with cattle being the biggest contributors.

Food waste accounts for 8-10% of global emissions - if it were a country, it would be the 3rd largest emitter.

Cement production alone accounts for about 8% of global CO2 emissions.

The fashion industry contributes about 10% of global emissions, more than aviation and shipping combined.

Climate change is expected to cause 250,000 additional deaths per year between 2030 and 2050.

Heat-related deaths have increased by 68% since 2000, with elderly populations most at risk.

Air pollution from fossil fuels causes about 8.7 million deaths per year - 1 in 5 deaths globally.

Climate change is expanding the range of disease-carrying mosquitoes, increasing malaria and dengue risk.

Crop yields could decline by up to 25% by 2050, threatening food security for billions.

About 2 billion people already experience high water stress, a number that will grow with warming.

Climate change disproportionately affects the world's poorest populations, who contribute least to emissions.

Climate anxiety is affecting mental health worldwide, especially among young people.

Small island nations face existential threats from rising seas, with some at risk of becoming uninhabitable.

Renewable energy capacity grew by a record 473 GW in 2023, led by solar power.

Electric vehicle sales have grown from 2% to over 18% of new car sales globally since 2020.

Wind and solar now provide about 12% of global electricity, up from less than 2% in 2010.

Over 140 countries have pledged to reach net-zero emissions, covering about 90% of global GDP.

Planting 1 trillion trees could capture up to 205 billion tons of carbon over their lifetime.

Improving energy efficiency could reduce emissions by 40% and save $4 trillion annually by 2040.

A plant-based diet can reduce an individual's food-related emissions by up to 73%.

Carbon capture technology can remove CO2 directly from the air, though it's still scaling up.

Green hydrogen could decarbonize heavy industry and transport, reducing emissions by 20%.

We have about 6 years of current emissions left before exceeding the 1.5C carbon budget.

Emissions need to drop 43% by 2030 and reach net-zero by 2050 to limit warming to 1.5C.

Climate tipping points, like ice sheet collapse, could be triggered between 1.5C and 2C of warming.

The clean energy transition could create 18 million more jobs than it displaces by 2030.

Every fraction of a degree of warming matters - 1.5C vs 2C means 50% more people exposed to water scarcity.

With 3C of warming, the Amazon could release more carbon than it absorbs, accelerating climate change.

Some climate impacts are now irreversible, including ice sheet loss and sea level rise already locked in.

Global economic damages from climate change could reach $23 trillion annually by 2050 without action.

Investing $1 in climate adaptation can yield $2-10 in reduced damages and economic benefits.