Definitions - h

Habitat

The living place or "home" of a particular organism or biological community.

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Habitat Banking
In a similar manner to carbon offsets, in habitat banking landowners are encouraged to restore degraded land or protect virgin forest to enhance its conservation values.

In return, the landowner is permitted to sell credits to national or international companies or developers, enabling them to satisfy legal requirements compensating for the environmental impacts of their development projects in the region or elsewhere.

Although big in the US, where there is a $3bn market, habitat banking's global reach is nowhere near the size of carbon offsets.

Potential for schemes is particularly high in Central and South America, although concerns remain over monitoring and proving how effective projects really are.

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Haboob

A dust or sandstorm that forms as cold downdraft's from a thunderstorm turbulently lift dust and sand into the air.

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HADcrut

Climate change is a change in the statistical distribution of weather over periods of time that range from decades to millions of years. It can be a change in the average weather or a change in the distribution of weather events around an average (for example, greater or fewer extreme weather events). Climate change may be limited to a specific region, or may occur across the whole Earth.

In recent usage, especially in the context of environmental policy, climate change usually refers to changes in modern climate. It may be qualified as anthropogenic climate change, more generally known as global warming.

Wikipedia - Climate Change entry

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Halogen Bulbs

Halogen bulbs are a form of energy efficient lighting that use around 25 per cent less energy than traditional incandescent bulbs.

Like traditional bulbs, Halogen bulbs use a tungsten filament, but they use a halogen gas inside the bulb rather than argon or nitrogen, making the filament last longer.

Around half the size of traditional bulbs, they are most commonly used in fixed ceiling down-lighters.

It is expected that some lower-efficiency Halogen bulbs will be banned alongside incandescent bulbs under upcoming EU regulations, though the sale of higher efficiency models will still be permitted.

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Halon

Bromine-containing compounds with long atmospheric lifetimes whose breakdown in the stratosphere causes depletion of ozone. Halons are used in firefighting.

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Hazardous Waste

Byproducts of society with physical, chemical or infectious characteristics that pose hazards to the environment and human health when improperly handled.

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Heat Island Effect

A "dome" of elevated temperatures over an urban area caused by structural and pavement heat fluxes, and pollutant emissions.

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Heat Lightning

Distant lightning that illuminates the sky but is too far away for its thunder to be heard.

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Heat Pump

A heat pump is an electrically powered mechanical device that takes heat from one location and transfers it to another location. An air conditioner is an example of a heat pump in that it takes heat out of the interior space and then rejects that heat to the outdoors. However, a true heat pump can work in either direction, unlike an air conditioner; in that it can take heat out of an interior space, or it can put heat into an interior space.

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Heavy Industry

Manufacturing activities engaged in the conversion of large volumes of raw materials and partially processed materials into products of higher value; hallmarks of this form of industry are considerable capital investment in large machinery, heavy energy consumption, and final products of relatively low value per unit weight (see Light Industry).

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Hemp

The main uses of hemp fiber are rope, sacking, carpet, nets and webbing. Hemp is also being used in increasing quantities in paper manufacturing. The cellulose content is about 70%.

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Herbicide

A chemical pesticide designed to control or destroy plants, weeds, or grasses.

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High-fructose Corn Syrup

High-fructose corn syrup (HFCS) (also called glucose-fructose, isoglucose and glucose-fructose syrup) is a sweetener made from corn starch that has been processed by glucose isomerase to convert some of its glucose into fructose. HFCS was first marketed in the early 1970s by the Clinton Corn Processing Company, together with the Japanese Agency of Industrial Science and Technology where the enzyme was discovered in 1965.

As a sweetener, HFCS is often compared to granulated sugar, but manufacturing advantages of HFCS over sugar include that it is easier to handle and more cost-effective. 

Apart from comparisons between HFCS and table sugar, there is some evidence that the over-consumption of added sugar in any form, including HFCS, is a major health problem, especially for the onset of obesity.

Consuming added sugars, particularly as sweetened soft drinks, is strongly linked to weight gain. Also, like most sugars, HFCS can create addictive tendencies in those who consume it regularly in volume (see That Sugar Film for more details on how a high sugar 'Low Fat' diet can be dangerous to your health, and the addictive tendencies that result).

The World Health Organization has recommended that people limit their consumption of added sugars to 10% of calories, but experts say that typical consumption of empty calories in the United States is nearly twice that level.

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Hockey Stick Graph

The hockey stick graph refers to the plot of temperature over the last 1000 years that shows a gradual temperature decline, until the early 20th century - then there is a 'ramp up' in temperature to a point not previously obtained in the proceeding 1000 years; hence demonstrating man's effect on the climate through industrialization. Made famous (or infamous) by its use in the 'Inconvenient Truth'.

The 'significance' of the graph as a true indicator of temperature (and especially the effective unprecedented temperature increases) has been a point of strong debate since it was published some ten years ago. Also the way the graph has been presented (smoothed/unsmoothed with or without error bands or indications of data sources and combinations there of) has lead to further controversy and heated discussions. Also the fact only 1000 years are presented, when we have proxies that go back many thousands of years is also a point of discussion.

For more background information see here .

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Home Battery System

A Home Battery System is a system that is used to time shift cheap electricity to a more expensive time period by the use of a battery.


The batteries in such a system need to be able to be deep cycled typically on a daily basis to allow the system to pay for itself in a reasonable time frame. They are often combined with high efficiency inverters.

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Homosphere

The atmosphere up to 80 km (50 mi) in which the proportionality of principal gaseous constituents, such as oxygen and nitrogen, is constant.

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Horizontal Axis Wind Turbine

A "normal" wind turbine design, in which the shaft is parallel to the ground, and the blades are perpendicular to the ground.

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Hot Water Recirculator

A hot water recirculator is basically a pump that is put in at the furthest part of the hot water system in your house, this pump has a return line back to the hot water tank. A thermometer is used to control when the pump goes on, idea is that hotter water is kept in the pipe at all times, so reducing the time it takes for the hot water to 'appear' at the tap or shower head.

This is good for existing installations, but do make sure the pipes are well lagged. For new builds it is often easier to use a smaller bore pipe, so less water rests in the pipe so it draws from the hot water tank quicker. 

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Human Food Chain

The human food chain is the chain of food producers and consumers from the first producer to human consumption.

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Humidity

Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture, called the Absolute humidity. In everyday usage, it commonly refers to relative humidity, expressed as a percent in weather forecasts and on household humidistat's; it is so called because it measures the current absolute humidity relative to the maximum. Specific humidity is a ratio of the water vapor content of the mixture to the dry air content (on a mass basis). The water vapor content of the mixture can be measured either as mass per volume or as a partial pressure, depending on the usage.

In meteorology, humidity indicates the likelihood of precipitation, dew, or fog. High relative humidity reduces the effectiveness of sweating in cooling the body by reducing the rate of evaporation of moisture from the skin. This effect is calculated in a heat index table, used during summer weather.

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Humus

The substance which results from decay of plant or animal matter. Biodegradable matters form humus as they decompose.

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Hybrid Flow Battery

The hybrid flow battery uses one or more electroactive components deposited as a solid layer. In this case, the electrochemical cell contains one battery electrode and one fuel cell electrode. This type is limited in energy by the surface area of the electrode.

Hybrid flow batteries include the zinc-bromine, zinc–cerium and lead–acid flow batteries.

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Hybrid System

Energy Generation: A solar electric or photovoltaic system that includes other sources of electricity generation, such as wind or diesel generators.

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Hydro Electric

The process by which the mechanical energy of moving water is transferred by a rotating turbine to a generator, where it is converted to electric energy and conveyed along transmission lines.

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Hydrogenation

The treatment of plant oils or animal fats, primarily with hydrogen gas in a refining process, for the production of synthetic hydrocarbons.

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Hydrology

The science dealing with the properties, distribution, and circulation of water.

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Hydrolysis

The decomposition of organic compounds by interaction with water.

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Hydronic Floor Heating

Hydronic flooring heating is where a network of water carrying pipes are embedded into the floor to transfer heat from a heat source (say solar hot water) to the floor - thereby providing a comfortable living environment. The only downside with such systems is that they depend upon the Sun to provide the warmth, this is often out of cycle with the demand for heat - i.e. you need to be warm in the evening and during cloudy days. Thermal mass can help phase shift the heating but you will often require additional back up heating as well.

This is often something which can only be done on a new build as you need to build the pipes into the structure of the floor. An option after build is to use a roof space heat recovery system to transfer the hot air from the roof into the living space by way of a filter and fan set up. The advantage with this is that such a system can also provide cooling air in Winter (as the roof space cools quicker than the living space below at night).

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Hydroponics
The growing of plants, especially vegetables, in water containing essential mineral nutrients rather than in soil.

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Hydrosphere

The totality of water encompassing the Earth, comprising all the bodies of water; ice, and water vapor in the atmosphere.

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Hypothesis

A proposition tentatively assumed. Science tests the logical consequences of a hypothesis against facts that are known or that may be determined.

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