What is climate change?
Climate is the average weather in a place over many years. Climate change is a shift in those average conditions.
The rapid climate change we are now seeing is caused by humans using oil, gas and coal for their homes, factories and transport.
When these fossil fuels burn, they release greenhouse gases – mostly carbon dioxide (CO2). These gases trap the Sun’s heat and cause the planet’s temperature to rise.
The world is now about 1.2C warmer than it was in the 19th Century – and the amount of CO2 in the atmosphere has risen by 50%.
Temperature rises must slow down if we want to avoid the worst consequences of climate change, scientists say. They say global warming needs to be kept to 1.5C by 2100.
However, unless further action is taken, the planet could still warm by more than 2C by the end of this century.
A report in 2021 by the Climate Action Tracker group calculated that the world was heading for 2.4C of warming by the end of the century.
If nothing is done, scientists think global warming could exceed 4C in the future, leading to devastating heatwaves,
millions losing their homes to rising sea levels and irreversible loss of plant and animal species.
bbc.com
The Causes of Climate Change
Em resumo:
As atividades humanas (principalmente a queima de combustíveis fósseis) aumentaram fundamentalmente a concentração de gases de efeito estufa na atmosfera da Terra, aquecendo o planeta. Motores naturais, sem intervenção humana, levariam nosso planeta a um período de resfriamento.
Scientists attribute the global warming trend observed since the mid-20th century to the human expansion of the “greenhouse effect”1 — warming that results when the atmosphere traps heat radiating from Earth toward space.
Certain gases in the atmosphere block heat from escaping. Long-lived gases that remain semi-permanently in the atmosphere and do not respond physically or chemically to changes in temperature are described as “forcing” climate change. Gases, such as water vapor, which respond physically or chemically to changes in temperature are seen as “feedbacks.”
Gases that contribute to the greenhouse effect include:
- Water vapor. The most abundant greenhouse gas, but importantly, it acts as a feedback to the climate. Water vapor increases as the Earth’s atmosphere warms, but so does the possibility of clouds and precipitation, making these some of the most important feedback mechanisms to the greenhouse effect.
- Carbon dioxide (CO2). A minor but very important component of the atmosphere, carbon dioxide is released through natural processes such as respiration and volcano eruptions and through human activities such as deforestation, land use changes, and burning fossil fuels. Humans have increased atmospheric CO2 concentration by 48% since the Industrial Revolution began. This is the most important long-lived “forcing” of climate change.
- Methane. A hydrocarbon gas produced both through natural sources and human activities, including the decomposition of wastes in landfills, agriculture, and especially rice cultivation, as well as ruminant digestion and manure management associated with domestic livestock. On a molecule-for-molecule basis, methane is a far more active greenhouse gas than carbon dioxide, but also one which is much less abundant in the atmosphere.
- Nitrous oxide. A powerful greenhouse gas produced by soil cultivation practices, especially the use of commercial and organic fertilizers, fossil fuel combustion, nitric acid production, and biomass burning.
- Chlorofluorocarbons (CFCs). Synthetic compounds entirely of industrial origin used in a number of applications, but now largely regulated in production and release to the atmosphere by international agreement for their ability to contribute to destruction of the ozone layer. They are also greenhouse gases.
climate.nasa.gov
10 solutions for Climate Change
The enormity of global warming can be daunting and dispiriting. What can one person, or even one nation, do on their own to slow and reverse climate change?
Forego Fossil Fuels—The first challenge is eliminating the burning of coal, oil and, eventually, natural gas. This is perhaps the most daunting challenge as denizens of richer nations literally eat, wear, work, play and even sleep on the products made from such fossilized sunshine. And citizens of developing nations want and arguably deserve the same comforts, which are largely thanks to the energy stored in such fuels.
Infrastructure Upgrade—Buildings worldwide contribute around one third of all greenhouse gas emissions (43 percent in the U.S. alone), even though investing in thicker insulation and other cost-effective, temperature-regulating steps can save money in the long run. Electric grids are at capacity or overloaded, but power demands continue to rise. And bad roads can lower the fuel economy of even the most efficient vehicle. Investing in new infrastructure, or radically upgrading existing highways and transmission lines, would help cut greenhouse gas emissions and drive economic growth in developing countries.
Move Closer to Work—Transportation is the second leading source of greenhouse gas emissions in the U.S. (burning a single gallon of gasoline produces 20 pounds of CO2). But it doesn’t have to be that way.
One way to dramatically curtail transportation fuel needs is to move closer to work, use mass transit, or switch to walking, cycling or some other mode of transport that does not require anything other than human energy. There is also the option of working from home and telecommuting several days a week.
Consume Less—The easiest way to cut back on greenhouse gas emissions is simply to buy less stuff. Whether by forgoing an automobile or employing a reusable grocery sack, cutting back on consumption results in fewer fossil fuels being burned to extract, produce and ship products around the globe.
Think green when making purchases. For instance, if you are in the market for a new car, buy one that will last the longest and have the least impact on the environment. Thus, a used vehicle with a hybrid engine offers superior fuel efficiency over the long haul while saving the environmental impact of new car manufacture.
Be Efficient—A potentially simpler and even bigger impact can be made by doing more with less. Citizens of many developed countries are profligate wasters of energy, whether by speeding in a gas-guzzling sport-utility vehicle or leaving the lights on when not in a room.
Good driving—and good car maintenance, such as making sure tires are properly inflated—can limit the amount of greenhouse gas emissions from a vehicle and, perhaps more importantly, lower the frequency of payment at the pump.
Eat Smart, Go Vegetarian?—Corn grown in the U.S. requires barrels of oil for the fertilizer to grow it and the diesel fuel to harvest and transport it. Some grocery stores stock organic produce that do not require such fertilizers, but it is often shipped from halfway across the globe. And meat, whether beef, chicken or pork, requires pounds of feed to produce a pound of protein.
Choosing food items that balance nutrition, taste and ecological impact is no easy task. Foodstuffs often bear some nutritional information, but there is little to reveal how far a head of lettuce, for example, has traveled.
Stop Cutting Down Trees—Every year, 33 million acres of forest are cut down. Timber harvesting in the tropics alone contributes 1.5 billion metric tons of carbon to the atmosphere. That represents 20 percent of human-made greenhouse gas emissions and a source that could be avoided relatively easily.
Improved agricultural practices along with paper recycling and forest management—balancing the amount of wood taken out with the amount of new trees growing—could quickly eliminate this significant chunk of emissions.
Desconecte — Acredite ou não, os cidadãos dos EUA gastam mais dinheiro em eletricidade para alimentar dispositivos quando desligados do que quando ligados. Televisores, equipamentos de som, computadores, carregadores de bateria e uma série de outros aparelhos e aparelhos consomem mais energia quando aparentemente desligados, então desconecte-os.
Uma criança — Há pelo menos 6,6 bilhões de pessoas vivendo hoje, um número que as Nações Unidas prevêem que cresça para pelo menos nove bilhões em meados do século. O Programa Ambiental da ONU estima que são necessários 54 acres para sustentar um ser humano médio hoje – alimentos, roupas e outros recursos extraídos do planeta. Continuar esse crescimento populacional parece insustentável.
Future Fuels—Replacing fossil fuels may prove the great challenge of the 21st century. Many contenders exist, ranging from ethanol derived from crops to hydrogen electrolyzed out of water, but all of them have some drawbacks, too, and none are immediately available at the scale needed.
scientificamerican.com
Hong Kong airport targets net zero emissions by 2050
Airport Authority Hong Kong has set out a plan to meet net zero emissions by 2050, including deploying a fully electric vehicle fleet on the ground and funding new green technologies.
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Hong Kong International Airport, the world’s busiest cargo gateway and one of the busiest passenger airports, has pledged to achieve net zero emissions by 2050, with electric vehicles as the key to decarbonisation.
The Airport Authority Hong Kong (AAHK) aims to cut absolute carbon emissions by 55% by 2035 compared to 2018 levels, a benchmark that is similar to the one set by Lonon´s Heathrow Airport, which is working towards to achieve carbon neutrality by mid-2030s.
“Our target is net zero instead of neutrality so it’s quite clear to us that we will try not to pursue any offset at all, in particular for the midpoint of 2035,” said Peter Lee, general manager of sustainability at Hong Kong airport. “In terms of the 2050 ultimate target, I think we need to wait and see what technology is coming,” Lee added.
The aviation industry currently accounts for only 2.5% of the global carbon emissions. However, with the projected growth trends, the sector’s emissions set to climb despite dropping to much lower levels during 2020 due to the COVID-19 pandemic. Decarbonising will be instrumental to help nations and territories, including Hong Kong, to limit global warming under 1.5C above pre-industrials and to avoid a climate catastrophe.
To meet the 2035 target, AAHK has set out roadmaps to reduce direct emissions at the airport as well as indirect emissions such as electricity consumption in a drafted carbon management action plan. For direct emission reduction, the airport will be electrifying all airside vehicles including tow trucks, container-loading, and passenger-steps vehicles by the end of the decade, making the switch towards more renewable diesel, and more than doubling the amount of airfield charging stations. Currently, a only fifth of the ground service fleet is electric.
The airport will also install LED lighting and smart technology to better control energy efficiency and use for equipment such as air-conditioning, as well as develop new energy management solutions, to tackle indirect emissions.
AAHK plans to introduce a Business Partner Carbon Support Programme that will include a USD$2.56m (HKD$20m) Green Innovation and Technology Fund, to support the development and testing of new technologies to help meet the 2050 net-zero target. While the airport already features fuelling infrastructure to support the use of sustainable fuel (SAF), the fund could help scale up decarbonization measures in aircraft and at the airport.
“Innovation, capacity building, and collaboration hold the key to achieving the Net-Zero Carbon target,” Lee adds. “We are pleased to see the positive response from our business partners in support of decarbonization. With the collaborative effort of the airport community, we are fully committed to achieving this Net-Zero Carbon target in pursuit of our pledge to make HKIA the world’s greenest airport.”
earth.org
Climate Change is Threatening the Survival of Bear Species
Climate change and global temperature rises are impacting the food availability and hibernation cycles of bear populations around the world, threatening the survival of bear species, including the Asiatic black bear.
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Our Earth is heating up at an unprecedented rate. Climate change is leading to a cascade of changes in animal and plant habitats all across the globe, but its impact on bears, including the Asiatic black bear, is particularly significant. This is especially true regarding the bears’ wintering behaviours and, as a direct result, is leading to an increased chance of human-bear conflict and threatening its survival of the species.
Like their black and brown bear cousins of North America, Asiatic black bears have evolved in synergy with their natural habitats’ climate and food availability. These mammals are hardwired to exploit seasons of food abundance to survive other seasons of food scarcity, entering hibernation where winter food availability is scarce and winter denning is necessary for bear survival.
These circannual activity rhythms have a predictable effect on bear behaviour over the course of a year. Even at Animal Asia’s bear rescue centre in the foothills of Tam Dao National Park Vietnam, the bears’ hunger drives, caloric needs, and food preferences generally mirror wild observations. In late spring and summer, there is a gradual increase in appetite, peaking roughly mid-autumn (this period of gorging is known as hyperphagia). In winter, hunger drives begin to wane before gradually dropping to their lowest levels in spring, when the annual cycle starts again. Around one in every five of rescued bears chooses to hibernate through winter.
In autumn, to prepare for winter scarcity, bears will seek out and indulge in high-calorie foods to add fat reserves. One of the most important autumn food sources for bears is hard mast – acorns and beechnuts. Recent research carried out in Asiatic black bear habitats in Japan and Pakistan suggests climate change is likely reducing the coverage of both oak and beech forests, subsequently leading to a reduction in a critical autumn food source for bears. Without the autumnal glut of a hard mast to feast on, bears may be unable to store enough fat reserves to sustain themselves through winter.
Other research has shown that warmer temperatures have led North American black bears and brown bears entering their dens later as well as leaving them earlier than expected. In fact, for brown bears, every increase of 4°C sees bears leave their dens ten days early. For black bears, increases of just 1°C reduce hibernation by an average of six days. It has been hypothesised that by 2050, North American black bear hibernation could decline by 15 to 39 days. Bears will be waking early and leaving their dens to search for food during a time of year when much of their foraging grounds have yet to spring to life. Simply put, bears are responding to increasing temperatures much quicker than much of the plant and animal life that sustains them.
It’s not only hibernation behaviours that are being impacted by climate change. Recent research into wild Asiatic black bear populations from the Hindu Kush Himalayan region and Iran predicts that warming temperatures will see bears migrate to higher elevations At the same time, longer periods of warm weather will increase bear activity across the year. New higher-altitude environments may fail to provide new and active bear populations with enough food and other resources for survival.
Malnutrition and starving bears are of obvious concern here. Equally worrying is that bears with inadequate natural food sources are more likely to wander into human communities to forage. As human populations expand and encroach on dwindling wild bear habitats, the interface between human settlements and bear territory is increasing. Combined, all of these factors increase the chances of human-bear conflict.
While, of course, dangerous for humans, human-bear conflict is more often fatal for bears. In Asia, bears have been known to forage farming crops and predate on livestock, which can result in local farming communities retaliating with lethal force. Human-bear conflicts often result in bear deaths in countries without humane management options in place, such as the live relocation of “problem” wildlife. This puts yet more pressure on already vulnerable populations of wild bears.
The consequences of climate change are impacting our shared planet in myriad ways. As a global community, we are standing at the edge of a precipice. The onus is on each of us, as individuals, communities, or governments, to act. The influence of warming global temperatures on bears is unmistakable. Yet, the effects on countless other species across our shared planet are still unknown. We risk any number of ecological tipping points resulting in the mass extinction of species, reminding us yet again that the climate crisis is a biodiversity and wildlife crisis too.
earth.org
Earth will not wait. Neither do we.
