What is climate

Because the Earth is a system, where everything is connected, changes in one area can influence changes in all others. The consequences of climate change now include, among others, intense droughts, water scarcity, severe fires, rising sea levels, flooding, melting polar ice, catastrophic storms and declining biodiversity.

Climate change can affect our health, ability to grow food, housing, safety and work. Some of us are already more vulnerable to climate impacts, such as people living in small island nations and other developing countries. Conditions like sea-level rise and saltwater intrusion have advanced to the point where whole communities have had to relocate, and protracted droughts are putting people at risk of famine.

In a UN report, thousands of scientists and government reviewers agreed that limiting global temperature rise to no more than 1. Yet based on current national climate plans, global warming will reach 2.

The emissions that cause climate change come from every part of the world and affect everyone, but some countries produce much more than others. The least-emitting countries generate 3 per cent of total emissions. The 10 countries with the largest emissions contribute 68 per cent.

Everyone must take climate action, but people and countries creating more of the problem have a greater responsibility to act first. Many climate change solutions can deliver economic benefits while improving our lives and protecting the environment. Three broad categories of action are: cutting emissions, adapting to climate impacts and financing required adjustments.

Switching energy systems from fossil fuels to renewables like solar or wind will reduce the emissions driving climate change. But we have to start right now. While a growing coalition of countries is committing to net zero emissions by , about half of emissions cuts must be in place by to keep warming below 1. Fossil fuel production must decline by roughly 6 per cent per year between and Adapting to climate consequences protects people, homes, businesses, livelihoods, infrastructure and natural ecosystems.

It covers current impacts and those likely in the future. Adaptation will be required everywhere, but must be prioritized now for the most vulnerable people with the fewest resources to cope with climate hazards. Eventually the solar energy absorbed by Earth is returned to space as infrared heat radiation. In the process it interacts with the whole climate system—atmosphere, oceans, land surfaces and ice sheets. The flows of radiation in the atmosphere Figure 1. The main gases that make up the atmosphere, nitrogen and oxygen, do not interact with infrared radiation.

By doing this they impede the outward flow of infrared energy from Earth to space. The most important are water vapour, carbon dioxide CO 2 and methane. Global climate varies naturally over time scales from decades to thousands of years and longer. These natural variations can originate in two ways: from internal fluctuations that exchange energy, water and carbon between the atmosphere, oceans, land and ice, and from external influences on the climate system, including variations in the energy received from the sun and the effects of volcanic eruptions.

Human activities can also influence climate by changing concentrations of CO 2 and other greenhouse gases in the atmosphere Box 1. Today, human activities are directly increasing atmospheric concentrations of CO 2 , methane and nitrous oxide, plus some chemically manufactured greenhouse gases such as halocarbons Question 3. These humangenerated gases enhance the natural greenhouse effect and further warm the surface.

In addition to the direct effect, the warming that results from increased concentrations of long-lived greenhouse gases can be amplified by other processes. A key example is water vapour amplification Box 1.

Human activities are also increasing aerosols in the atmosphere, which reflect some incoming sunlight. This human-induced change offsets some of the warming from greenhouse gases. There are close connections between temperature, atmospheric water vapour, the extent of polar ice sheets and the concentrations of long-lived greenhouse gases especially CO 2 in the atmosphere.

These feedbacks occur on a wide range of time scales: those involving the atmosphere are typically rapid, while those involving deep oceans and ice sheets are slow and can cause delayed responses. Agriculture The development of agriculture was very dependent on climate. Ancient agricultural civilizations, such as those in Mesopotamia and India, flourished where the climate was mild.

Communities could grow crops every season, and experiment with different types of crops, livestock , and farming techniques.

The mild, Mediterranean climate in which the Roman Empire developed, for instance, allowed farmers to cultivate crops, such as wheat, olives, grapes, barley, and figs. Livestock included cattle, sheep, goats, pigs, and even honeybees.

Like the ancient Romans, ancient cultures of the Amazon Basin in South America were also able to develop agricultural practices. Today, farmers are still in tune with the climate.

They plant certain crops according to the expected amount of rainfall and the length of the growing season. When the weather does not follow the typical climate pattern, it can mean hard times for farmers and higher food costs for consumers. Climate Change Climate does not change from day to day like weather, but it does change over time.

The study of historic climate change is called paleoclimatology. Climate changes happen slowly over hundreds or even thousands of years. For example, periodic glacial periods have covered large portions of Earth with ice caps. For example, after the eruption of the island volcano of Krakatoa, Indonesia, in , winters and even summers in Asia and Europe were colder and darker. Volcanic ash blocked the sun. Farmers had to adjust to shorter, weaker growing seasons. Climates around the world were changed for years.

The Little Ice Age was not a true glacial period , but describes colder climates around the world. In Europe, canals in Great Britain and the Netherlands were often frozen solid, allowing for ice skating. In North America, European colonists reported especially harsh winters. Global Warming Since the Industrial Revolution of the 19th century, human activity has begun to impact climate. In this way, they act like the glass walls of a greenhouse.

The greenhouse effect is a natural phenomenon and keeps Earth warm enough to sustain life. However, human activities that include burning fossil fuels and cutting down forests release greenhouse gases into the atmosphere at an unprecedented rate. The current period of climate change has been documented by rising temperatures, melting glaciers, and more intense weather phenomena. Sixteen of the last 17 warmest years on record have occurred in the 21st century.

According to NASA, not only was the warmest year on record, but eight of the 12 months that make up the year were the warmest on record for those respective months. The current period of climate change is also associated with the massive retreat of glaciers, ice sheets, and sea ice. In , one of the largest icebergs ever recorded entered the ocean as a huge chunk of the Larsen C ice shelf broke off the Antarctic Peninsula.

Warmer ocean temperatures and warmer ambient air temperatures likely contributed to the fracturing of the ice shelf and the massive Antarctic ice sheet associated with it.

Finally, both the extent and thickness of Arctic sea ice has declined rapidly during the past several decades. The famed Northwest Passage , the treacherous route connecting the North Atlantic and North Pacific ocean basins, is now habitually free of ice and safe enough for cruise ships to navigate.

Melting glaciers and ice sheets, as well as expansion of seawater as it warms, have contributed to unprecedented sea level rise. Sea level rises at about 2. Increasing temperatures can change the climate impacts and even the classification of a region. For instance, low-lying islands may be flooded as seawater rises.

Heat in the atmosphere may increase the interaction of diverse weather systems. Unusually arid climates in a semiarid region may prolong droughts, for instance. In regions with mild climates, the increased atmospheric moisture associated with humid climates may increase the likelihood of hurricanes and typhoons. Climate change is also impacting organisms and species range. Organisms that have adapted to one climate may have to migrate or adapt to warmer temperatures.

Manatees, for instance, are marine mammals native to tropical waters. Polar bear populations, on the other hand, are venturing farther south as Arctic sea ice becomes more scarce. Climate change can be mitigated through reducing greenhouse- gas emissions. This can mean investing in new technologies, relying more on renewable energy sources, making older equipment more energy-efficient, or changing consumer behavior.

The coldest temperature ever recorded at ground level on Earth— Also called Ancestral Puebloans. Also called a subarctic or tundra climate. Continental climates are only found in the Northern Hemisphere. Gas molecules are in constant, random motion. Also called a warm summer climate. Hurricanes are the same thing as typhoons, but usually located in the Atlantic Ocean region. Also known as the Monsoon Zone.

Monsoon usually refers to the winds of the Indian Ocean and South Asia, which often bring heavy rains. Regions are the basic units of geography. The current sea level rise is 1. Range also refers to the geographic distribution of a particular species. Also called a boreal or tundra climate. Also called lithospheric plate. Also called a rain forest climate. Typhoons are the same thing as hurricanes, but usually located in the Pacific or Indian Ocean region. Also called a humid continental climate.

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You cannot download interactives. Climate describes the average weather conditions of a particular place over a 30 year period. All places on earth have their own climates.

Different from weather events, which are short-term and temporary phenomenon, climates are usually steady and predictable, and shape how organisms and human civilizations evolve and adapt in any given region. However, climates are not always permanent, and can change drastically due to human activity. Explore the world's climates and how they affect local regions and the planet with this curated collection of resources. Weathering is the process of the weakening and breakdown of rocks, metals, and manmade objects.

There are two main types of weathering: chemical and physical. An example of chemical weathering is acid rain. Caused mostly by the burning of fossil fuels, acid rain is a form of precipitation with high levels of sulfuric acid, which can cause erosion in the materials in which it comes in contact.

An example of physical weathering is wind blowing across the desert playas. This process causes rocks to form a specific pyramid-like shape and they are called ventifacts. Select from these resources to teach about the process of weathering in your classroom. A biome is an area classified according to the species that live in that location.

Temperature range, soil type, and the amount of light and water are unique to a particular place and form the niches for specific species allowing scientists to define the biome.

However, scientists disagree on how many biomes exist. Some count six forest, grassland, freshwater, marine, desert, and tundra , others eight separating two types of forests and adding tropical savannah , and still others are more specific and count as many as 11 biomes.

Use these resources to teach middle school students about biomes around the world. An abiotic factor is a non-living part of an ecosystem that shapes its environment. In a terrestrial ecosystem, examples might include temperature, light, and water.