climate noun The general weather conditions typical of an area over a long period of time. The region's dry climate makes it well suited for growing grapes. + weather noun The state of the atmosphere at a particular time and place, including temperature, wind, and rain. The weather turned cold and rainy just as the picnic was about to start. + atmosphere noun The mixture of gases surrounding a planet, or the overall mood or feeling of a place. Earth's atmosphere protects us from harmful radiation from the sun. + temperature noun A measure of how hot or cold something is, typically expressed in degrees. The temperature dropped sharply as soon as the sun went down. + greenhouse gas noun A gas, such as carbon dioxide or methane, that traps heat in Earth's atmosphere and contributes to warming. Burning fossil fuels releases large amounts of greenhouse gas into the atmosphere. + emission noun Something released or discharged into the air, especially gas, radiation, or light. The factory reduced its carbon emission after installing new filtering equipment. + carbon footprint noun The total amount of greenhouse gases produced by a person's or organization's activities. Flying less is one simple way to reduce your carbon footprint. + fossil fuel noun A natural fuel such as coal, oil, or gas formed from the remains of ancient organisms. Many countries are trying to reduce their reliance on fossil fuels for electricity. + renewable adjective Able to be replaced naturally or continue indefinitely, or capable of being extended or renewed. Solar and wind are renewable sources of energy that will not run out. + sustainability noun The capacity to maintain a process, resource, or system over time without depleting it or causing lasting damage. The company published a report detailing its progress toward greater sustainability in packaging and shipping. + drought noun A long period of unusually low rainfall that leads to a shortage of water. The drought forced farmers to ration water carefully across their fields. + precipitation noun Water that falls from clouds as rain, snow, hail, or another liquid or frozen form. Most of the winter precipitation here falls as snow. + humidity noun The amount of water vapor present in the air. The humidity made the summer afternoon feel hotter than the thermometer showed. + ecosystem noun The living things in an area together with their nonliving surroundings and the ways they interact. The pond ecosystem includes insects, plants, water, and sediment. + biodiversity noun The variety of plant and animal life found in a particular habitat or the world. Rainforests contain an extraordinary level of biodiversity compared to most other ecosystems. + deforestation noun The large-scale clearing of forests, typically for farming, logging, or development. Deforestation in the region has led to significant loss of wildlife habitat. + pollution noun The presence of harmful or unwanted substances in the environment, causing damage to air, water, land, or living things. Air pollution in the city worsens noticeably during the hot summer months. + ozone noun A form of oxygen with three atoms per molecule that forms a protective layer in the upper atmosphere. Scientists monitor the hole in the ozone layer above Antarctica every year. + glacier noun A large, slow-moving mass of ice formed from compacted snow over long periods on land. The glacier has retreated noticeably up the valley over the past fifty years. + sea level noun The average height of the ocean's surface, used as a standard reference point for measuring land elevation. The city sits barely two meters above sea level, so it floods easily during storms. + erosion noun The gradual wearing away of soil, rock, or land by natural forces such as wind, water, or ice. Years of coastal erosion have caused the cliff to shrink noticeably. + adaptation noun The process of changing to become better suited to new conditions, or a modified version of an original work. The lizard's coloring is an adaptation that helps it hide from predators. + mitigation noun The action of reducing the severity, seriousness, or harmful effects of something. The city invested in flood mitigation projects along the riverbank. + resilience noun The ability to recover quickly from difficulties, setbacks, or hardship. Her resilience after the accident inspired everyone who watched her recovery. + carbon dioxide noun A colorless gas produced by breathing, burning fuel, and decay, and absorbed by plants. Trees absorb carbon dioxide from the air and release oxygen in return. + methane noun A colorless, odorless, flammable gas made of carbon and hydrogen that is the main component of natural gas. Cows release methane as part of their digestion, which contributes to greenhouse gas emissions. + warming noun The process of becoming warmer, especially the gradual rise in the earth's average temperature. Scientists have linked global warming to rising sea levels and melting glaciers. + ice cap noun A thick, permanent layer of ice and snow covering a large area of land, especially near the poles. The Greenland ice cap holds enough frozen water to raise sea levels significantly if it melted. + permafrost noun A layer of soil beneath the earth's surface that stays frozen throughout the year. Scientists worry that thawing permafrost in the Arctic could release trapped greenhouse gases. + conservation noun The careful protection and management of natural resources, wildlife, or historic sites to prevent loss or damage. The organization funds conservation projects to protect endangered rainforest habitats. +