Assistant Professor, Degree College, Gilgit
“Climate change is not science fiction”, Arnold Schwarzenegger, former Governor of California and founder of R20 Regions of Climate Action cautions us and further argues that “it’s the challenge of our times,” while referring the severe and everlasting negative impacts of climate change. None of us has forgot the devastating impact of 2010 flood in Pakistan in which hundreds of people lost their lives and billions of property vanished with the wrath of flood water. Attabad lake formation in Hunza in January 2010 was another impact of climate change which also has created much havoc and uncertainties in the north of Pakistan. The notion of climate change has attracted the minds of many people whenever such a natural catastrophic event occurs. Therefore, some essential questions must be answered before understanding the impacts of climate change. What is climate and how climate change takes place? Is it a global phenomenon or some regions of the world like the mountainous areas in which we use to live reflect at different scale? Which are main areas where climate change has multiplier effect?
The climate of a region or city is its average weather conditions for a long period of time, whereas, weather is the short-term changes we see in temperature, clouds, precipitation, humidity and wind in a region or a city. Weather can vary greatly from one day to the next, or even within the same day. The climate of a region or city is its weather averaged over many years. Earth’s climate is the average of all the world’s regional climates. Climate change, thus, is a change in the average weather of a region or city. Climate change is also a change in Earth’s overall climate. This could be a change in Earth’s average temperature, or it could be a change in Earth’s typical precipitation patterns. Earth’s climate is always changing. In the past, Earth’s climate has gone through warmer and cooler periods, each lasting thousands of years.
Why the Earth climate takes changes?
Although climate change is a universally accepted truth but still there are some doubts on this notion. This is because the phenomenon is also caused by some natural forces. These include; changes in Earth’s orbit and the amount of energy received from the sun, volcanic eruption and ocean changes are some of the natural causes of climate change. Most scientists and scientific bodies agree that recent warming can’t be explained by explicit nature. These scientists believe that most of the warming since the mid-1900s is due to the burning of coal, oil and gas. Burning of these hydrocarbons is how we produce most of the energy that we use every day. This burning adds heat-trapping gases, such as carbon dioxide, into the air. These gases are called greenhouse gases which accumulate earth’s temperature thus accentuate global warming. The UN Framework Convention on Climate Change (UNFCCC), in its Article 1, defines climate change as: “a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere”. The climate change we are experiencing since the industrial revolution has anthropogenic origin and tend to be more serious as natural processes have nothing to do with remedial measures.
Fig.1. Glaciers of the world show retreating behavour since 1960. It is the time from which earth witnessed a sharp increase in air temperature.
What is the impact of earth’s warming climate? Some impacts are already visible. Since 1850s the world has witnessed increasing surface temperature with more than 1°C while the last 30 years (1983-2012) regarded as the warmest period of the last 1400 years. As a result, snow and ice cover is decreasing (Fig.1) and sea level is increasing. The frequency and severity of droughts and heat waves are increasing. The warming climate likely will cause more floods, droughts and heat waves. The heat waves may get hotter, and hurricanes may get stronger. Rainfall patterns and growing seasons are shifting. Intense droughts can lead to destructive wildfires, failed crops, and low water supplies, many of which are deeply affecting most parts of the world. Oceans temperatures are also increasing. Oceans evaporate more water as the air right near the surface gets warmer. The result? More floods, more hurricanes, and more extreme precipitation events.
Fast glacier melting is an indicator of climate change
Freshwater is the most valuable resource for mankind and is essential for human health, prosperity and security. In South Asia and China, about 1.5 billion people depend either directly or indirectly on water flowing down from the Hindu Kush Himalayas (HKH), thus these mountains called ‘Water Towers of Asia’. Any adverse effect on these mountains means the suffering and starvation of 1/4th population of the world. Mountain areas are particularly vulnerable to climate change, and the HKH region has no exception to it. Along with a rapidly increasing population which is placing greater demands on water resources, climate change is affecting water availability throughout the HKH and beyond. It has been observed that the region’s climate has been changing fast and will continue to do so in the future. The region is warming about three times faster than the global average and further warming can be expected even under a low emissions scenario, especially at higher altitudes and during the winter season. By 2050, temperatures are projected to rise here by 1–2°C on average and even 4–5°C in some places (ICIMOD, 2014). Precipitation across the region could change by up to 25%, increasing in some areas whilst decreasing in others. Extreme rainfall events are projected to become more intense, increasing the risk of catastrophic flood events.
Fig.2 Valley glaciers formed in the avalanche-nourished depressions called ‘cirque’ and move downwards due to gravitational force and heavy mass. Meting takes place on their snout position which is the least elevated area from where stream comes out. (Source: Author Aug, 2015 Bagrote Glacier, Karakoram Ranges, Pakistan)
The cryosphere (glacier and snow) of the Hindu Kush-Himalayan region plays a significant role in the regional climate system and is also a sensitive indicator of global climate change. Climate change is a major driver affecting the cryospheric environment, threatening the freshwater reserves and posing increased risks from climate-induced hazards to the mountain region and its immediate downstream communities. The glaciers in much of the region show signs of shrinking, melting and fast retreating which could lead to the formation and expansion of glacial lakes outburst floods (GLOFs). International Commission for Snow and Ice (ICSI) warned us in 1999 that glaciers in Himalayas are receding faster than in any other part of the world. IPCC in its Assessment Report 2014 estimated that Western Himalayan glaciers will retreat for the next 50 years causing higher variability and more floods and droughts. Then the glacier reservoirs will be empty, resulting in decrease of flows by up to 30% to 40% over the subsequent fifty years.
Some important glaciers of Northern Pakistan is presented in the below table.1 in which glaciers has reflected the fast retreating behavour due to rising air temperature. Gulkin glacier has lost its 12% area during 16 years, whereas, Jutmau glacier in Karakoram Ranges lost its 28% area during the same period.
Table.1 Karakoram glaciers show the fastest retreating rate during the study from 1992 to 2008(Source: Badar Ghauri, IST, 2016)
In a recent climate change study by this author in Northern Pakistan, remote sensing techniques applied on Rakaposhi-Diran Group of glaciers of Karakoram Ranges. Landsat satellite imageries used to monitor the glacier fluctuations since 1972. Remote sensing is the most modern scientific method of investigation of physical objects at far off distance. High elevated mountain areas, homes of these glaciers, are inaccessible and dangerous parts so satellite images are the only easy method of investigation. It has been observed that the glacier area has been drastically reduced from 275 Sq.Km to 267 Sq.Km in 36 years (Fig.3).
Fig.3. Rakaposhi-Diran Glaciers reduced their area due to climate change
The topography, terrain, physical features and most of all changing climate of the Hindu Kush Himalayas also make this region inherently unstable and prone to hazards. These include floods, landslides, avalanches and other natural disasters. Steep slopes, prolonged or intense periods of heavy rainfall and unstable bedrock all promote the conditions for such hazards. Glacial melting, as a result of climate change is likely to increase and result in more floods and severe damage to lives and property. The devastating impacts of climate related hazards and disasters can be minimized if the society has prepared mitigation and adaptation measures. Structural changes (such as flood preventive measures) and nonstructural changes (such as the implementation and enforcement of building codes, land use planning laws and early-warning systems) are needed to reduce exposure, vulnerability and risks for populations, as well as to adequately manage disaster events if they occur.