The first half of the Holocene period was warm. Then there was a cooling trend that lasted approximately 5,000 years. About 200 years ago, temperatures began to rise steadily.

The past 10 years have been hotter than 80 per cent of the past 11,300 years.

The research shows that a one-degree temperature variation that took 11,300 years to occur has been repeated in the last 150 years from the start of the Industrial Revolution.

If the scientists' forecasts are correct, the planet will be warmer in year 2100 than it has been for 11,300 years.

The destruction of the ozone layer is primarily caused when the amount of gases that contain chlorine begins to increase in the environment. Today, the number-two producer of human-caused greenhouse effects is methane, the main constituent of natural gas. When initially released, methane is about 100 times more potent than carbon dioxide, but its lifetime in the atmosphere is much shorter — about a decade, unlike carbon dioxide’s residence time of centuries. When averaged over a 20-year period, methane’s “greenhouse gas equivalency” is about 72 times that of carbon dioxide, but when looked at on a timescale of 100 years, that equivalency drops to just 25 times.

Food is the second largest contributor to global warming. When food rots, it releases methane, a greenhouse gas, which the U.S. Environmental Protection Agency says is 25 times more damaging to the environment than carbon dioxide. Landfills account for more than a third of all methane emissions in the U.S. Internationally many countries are trying to reduce food waste and conducting many projects to reduce food waste.

How to Reduce Food Waste

a. Waste reduction at source

Pre Consumer Food Waste can be reduced by:

Conducting a Waste Audit and modifying purchasing quantities, timing, production and handling practices, reviewing menus, secondary uses like converting excess rice to fried rice.

Post-consumer food waste can be reduced by:

Reducing excessive portion sizes and additional serving, if required especially in institutions like colleges and industrial canteens.

Identifying menu items causing more left over on the diner's plate.

Most of the major supermarket retailers in the west work with NGOs to reduce the food thrown away like providing recipes, how to store food better, types and sizes of products sold, the way food is sold (eg."half price" rather than "two for one").

Selling farm produce direct to consumers through farmers' markets and farm shops will also help.

Changing consumer attitudes

The best way to eliminate food waste is to not create it in the first place.

Consumers in rich countries buy more food than they need – Like "Buy three, pay two" promotions, oversized ready-to-eat meals, fixed-price buffets that spur customers to heap their plates.

Consumer level Reduction Actions:

Plan your menu and shop for just those things on your menu.

Buy in quantities that you realistically need and will use. If you buy in bulk, make sure to store them properly and use them in time.

Think "what do we have to eat" instead of "what do I want to eat?" Use up the food you already bought and have in the house instead of buying more.

Re-Use Actions:

Use up your leftovers - Internet has many websites giving recipes for using leftover foods such as www.lovefoodhatewaste.com/recipes.

Consider preserving or canning surplus fruits and vegetables.

b. Feed Hungry People:

Even in rich countries, there are always poor people who are not sure where they will find their next meal. Non-perishable and unspoiled perishable food are donated to local food banks by restaurants, caterers, corporate dining rooms, hotels, and other food establishments for prompt distribution to hungry people in their communities.

c. Feed Animals

Farmers often use food discards to feed their livestock. Excess food may also be provided to zoos for feeding animals in consultation with animal feeding experts. Some companies also convert food discards into commercial animal and pet food.

d. Industrial Uses

Rendering Fats, Oils, and Grease

Liquid fats and solid meat products can be converted into animal food, cosmetics, soap, and other products. Fats, oils, and grease (FOGS) are also converted into biodiesel fuel, which is biodegradable and nontoxic. This process recovers energy and recycles waste oils that are either dumped in landfills or flushed down drains, clogging pipes.

Anaerobic digestion

Anaerobic digestion breaks down organic matter to generate biogas, which can be burned for energy. The material that remains after digestion, when composted  produces a valuable soil amendment and zero landfill waste.

e. Composting

Composting creates an incredibly beneficial product from organic waste that would otherwise have been land filled.

Environmental Benefits

Throwing food wastes resources like energy, water and packaging used in food production, transportation and storage. Reducing, recovering, and recycling food waste diverts organic materials from landfills and incinerators, reducing GHG emissions from landfills and waste combustion.

The use of recycled food waste (compost) has many environmental benefits such as: improving soil health and structure; increasing drought resistance; reducing the need for supplemental water, fertilizers, and pesticides.

An additional benefit of food waste reduction is improved sanitation, public safety and health.