A reality check on global warming

Global warming is already having a massive and costly effect on our beautiful earth, community, health and climate. How this warming can be compared to the earlier changes in Earth's climate? How we may be certain that human-released greenhouse gases are producing the warming? How much more will the Earth warm? How will the Earth respond? Answering these questions is possibly the most significant challenge of our times.

If we do not take immediate action to reduce global warming emissions, these impacts will continue to intensify, grow ever more costly and damaging, and increasingly affect the entire planet including us, our family, community, and the future generation. This is a very alarming, sensitive, frightening, dangerous and desperately necessary issue.

The term global warming denotes the phenomenon of rising average air temperatures near the surface of Earth over the past few centuries. Experts have gathered detailed observations of various weather phenomena (such as temperatures, rainfall, and storms) and related influences on climate (such as ocean currents and the atmosphere's chemical composition). All these indicate that climate has changed over almost every possible timescale since the beginning of geologic time. The influence of human activities at least from the beginning of the industrial revolution has been deeply woven into the very fabric of climate change.

Scientists and analysts say global warming surfaces when carbon dioxide (CO2) and other air contaminants and greenhouse gases gather in the atmosphere and absorb sunlight and solar radiation bounced off the earth's surface. Radiation usually escapes into space. However, these pollutants, which may last for years to centuries in the atmosphere, trap the heat and cause the earth to get hotter and hotter and this is what's known as the greenhouse effect. So global warming is related to the unusually rapid increase in Earth's average surface temperature over the past centuries mainly due to the greenhouse effect.

The earth's temperature begins with the sun. Roughly 30 per cent of incoming sunlight is reflected back into the space by bright surfaces like clouds and ice. Of the remaining 70 per cent, the most is absorbed by land and ocean, and the remaining is absorbed by the atmosphere. The absorbed solar energy heats up our planet. For example, the rocks, the air, and the seas warm, they radiate 'heat' energy called thermal infrared radiation.

Scientists are now concerned that humans, over the yesteryears, have been artificially raising the concentration of greenhouse gases in the atmosphere at an ever-increasing rate, mostly by way of burning fossil fuels, also by destroying the carbon-absorbing forests.

Every year, the scientists learn more about the consequences of global warming and many agree that environmental, economic, and health consequences are likely to occur if current trends continue.

Below is just a smattering of what we may look forward to:

• The average global sea level has increased eight inches since 19th century and it is now rising much faster. Global warming is now accelerating the rate of sea level rise - thereby increasing flooding risks to the low-lying communities and high-risk coastal properties whose development has been encouraged by today's flood insurance system.
  
  
• Wildfires are increasing and wildfire season is getting longer with the rise in temperatures. Higher spring and summer temperatures and earlier spring snowmelt result in forests that are hotter and drier for longer periods of time, priming conditions for wildfires to burn and spread.
  
  
• Rising temperatures will likely lead to increased air pollution, a longer and more intense allergy season, the spread of insect-borne diseases, more frequent and dangerous heat waves, and heavier rainstorms and flooding. All of these changes pose serious and costly risks to public health.
  
  
• Dangerously, hot weather is already occurring more frequently and scientists expect heat waves to become more frequent and severe as global warming intensifies. This increase in heat waves creates serious health risks, and can lead to heat exhaustion, heat stroke and aggravate existing medical conditions.
  
  
• Temperatures are rising in the planet's Polar Regions and the vast majority of the world's glaciers are melting faster than new snow and ice can replace them. Scientists expect the rate of melting to accelerate with serious effects on sealevel rise in future.
  
  
• Global warming has the potential to seriously disrupt our food supply, drive costs upward, and affect everything from coffee to cattle, from basic food crops to the garden in our backyard.
  
  
• Coral reefs seem to be destined for destruction. According to the Union of Concerned Scientists of USA, coral reefs are one of the most productive ecosystems on Earth, providing many critical services to fisheries, shoreline protection, tourism, and to medicine. The coral reefs are also believed to be among the most sensitive ecosystems to long-term climate change. High temperature causes long-term damage to coral reefs. Scientists, too, have revealed that sustained water temperatures of as little as one degree Celsius above normal summer maxima can cause irreversible damage.
  
  
• A changing climate also affects the range of plants and animals, changing their behaviour and causing disruptions up and down the food chain. The range of some warm-weather species will expand while those that depend on cooler environments will face shrinking habitats and potential loss.

Other effects of global warming include, but are not limited to, the following:

• An increase in extreme weather events
• Widespread forest death in the rocky mountains
• More destructive hurricanes
• National landmarks at risk
• Changing seasons
• Increased pressure on groundwater supplies
• Heavier precipitation and flooding
• The potential for rapid climate change etc.

Atmosphere today contains huge greenhouse gas, so more of the ultraviolet energy produced by the surface ends up being absorbed by the atmosphere. Subsequently, some of the extra energy from a warmer atmosphere issues back down to the surface, earth's surface temperature rises. By increasing the awareness of greenhouse gases, we are making Earth's atmosphere a more efficient greenhouse. A strong debate is in progress over the extent and seriousness of rising surface temperatures, the effects of past and future warming on human life, and the need for action to reduce future warming and deal with its consequences.

We can, however, reduce our carbon footprint on our own by following a few easy steps. Saving energy can be made a part of our daily routine and it's very much our decision as consumer. We can look for home appliances with the Energy Star label during the time of our shopping as they meet a higher standard for energy efficiency. While buying a car, let's look for one with the highest gas mileage and lowest emissions. We may also reduce our emissions by opting for public transportation or car sharing when possible.

Let's voice our support for climate-friendly and climate change awareness policies, and tell users and campaigners that transitioning from dirty fossil fuels to clean power should be a top priority as it's vital to build healthy, more secure communities. Let's campaign and work together to make our world a better place.

Taslim Ahammad is Assistant Professor at Bangabandhu Sheikh Mujibur Rahman Science and Technology

University, Gopalganj.

taslim.ahammad@gmail.com