Climate change has a great influence on human health. Climate changes particularly change in weather extremes affect our environment which provides us food, water, shelter, and clean air. The impacts of climate change are increasing day by day. Due to increased industrial emissions and the global phenomenon of greenhouse gases cause an increase in temperature. THE 2014 US National Climate Assessment found that due to the rise in temperature the frequency and intensity of some extreme weather events also increase. These extreme weather events include rising sea level due to melting of glaciers, it results in the flood which affects/disturb the lives of people and also affects our country’s economy.

Severe weather events include hurricanes, tornados, drought, etc. Climate change causes the temperature both rise or fall also causes a shift in Precipitation, changes in precipitation and runoff, combined with changes in consumption and have reduced surface and groundwater supplies in many areas. Droughts also result in less rainfall due to which crop productivity reduces and there is a problem in meeting the rising food demands of the public. Due to the shortage of food, many people affect it cause malnutrition and in severe the reduction in food availability cause death. There are changes in some other extreme weather events over the several decades. Due to the rise in temperature Intense heat waves have become frequent especially in the West. These intense heat waves cause the death of old age people because they have not the capacity to bear such a great rise in temperature.

Due to climate change, greenhouse gas concentration also increases. Due to the temperature rise, the productivity of cash crops such as wheat and rice also affect. Climate change also causes Infectious diseases that are spread via contaminated water and food. Water-related diseases are a major problem in poor countries where water supply and sanitation often are inadequate. The outbreak of chorea, typhoid, and diarrheal diseases can occur after flooding if the floodwater is contaminated with human and animal waste. While droughts reduce the availability of water for washing, sanitation also the risk of diseases increases. Communicable diseases have resulted due to population growth, urbanization, changes in agricultural practices, deforestation, and breakdown in public health infrastructure.

Communicable diseases such as malaria are caused due to increased mosquito abundance which is due to flooding. The abundance of rainfall events causes viral diseases such as Dengue, yellow fever. Vector-borne disease transmission is sensitive to temperature fluctuations. When temperature tends to increase biting behaviors of Vector increased. Over 2.5 billion people are at risk and therefore, estimated to be 0.5 billion cases and more than 1million deaths from malaria per year. Feminine conditions may have contributed to excess mortality during a historical epidemic of malaria. Many deaths occurred after the end of droughts. The prominent cause was malaria. When drought-breaking rains increased Vector abundance. Some indicators such as age and disease profile, Socioeconomic status, housing condition, the prevalence of air conditioning. These factors also have a counter part in individuals as risk factors for heat-related mortality, morbidity. Such as the presence of air conditioning at the time of death. An increase in temperature due to global warming results in a forest fire. The direct effect of fire is on human health. Forest fires result in air pollution and respiratory disorders such as asthma.

Global warming has both direct and indirect health effects. Direct effects include exposure to extreme weather events such as heatwaves. Indirect effects include disruption to economic and social activity, which can impact health if, for example, it reduces people's ability to earn a livelihood. Other health-related effects arise from environmental degradation, diseases carried by vectors, food and waterborne infections, changes to food security, and impacts on mental health. In some cases, there can be health benefits, but in the clear majority of observed and predicted cases, the health impacts of climate change are negative.

Some 1.8 billion (more than 70%) of the population at risk for dengue worldwide live in member states of the WHO South-East Asia Region and Western Pacific Region, which bear nearly 75% of the current global disease burden due to dengue. The Asia Pacific Dengue Strategic Plan for both regions (2008--2015) has been prepared in consultation with member countries and development partners in response to the increasing threat from dengue, which is spreading to new geographical areas and causing high mortality during the early phase of outbreaks. The strategic plan aims to aid countries to reverse the rising trend of dengue by enhancing their preparedness to detect, characterize and contain outbreaks rapidly and to stop the spread to new areas.

In April 2020 the UNEP ( United Nations Environment Programme) published 2 short videos explaining the link between nature destruction (including climate change), wildlife trade, and COVID-19 pandemic and created a section in its site dedicated to the issue. Part of the causes of the COVID-19 pandemic can be environmental, like climate change and deforestation. According to the World Bank, climate change can increase the risk of an epidemic like the coronavirus in several ways including by causing deforestation. Deforestation is responsible for 31% of zoonotic diseases. A 2021 study found possible links between climate change and transmission of COVID-19 by bats. The authors suggest that climate-driven changes in the distribution and richness of bat species harboring coronaviruses may have occurred in eastern Asian hotspots (southern China, Myanmar, and Laos), constituting a driver behind the evolution and spread of the virus. People eat bush meat due to food insecurity caused by climate change. Bushmeat like a bat that is linked to the outbreak. The number of pandemics increases in the 21st century due to several factors including climate change.

Global climate change will have substantial negative impacts on mental health and wellbeing, especially for vulnerable populations and those with pre-existing serious mental illness. Climate change does not impact everyone equally; those of lower economic and social status are at greater risk and experience more devastating impacts. Climate change may also have a physiological effect on the brain, in addition to its psychological impacts. A study published in April 2020 found that by the end of the 21st-century people could be exposed to avoidable indoor CO2 levels of up to 1400 ppm, triple the amount commonly experienced outdoors today.

Plants' nutrients are affected by the increased atmospheric concentration of Carbon dioxide. When the carbon dioxide concentration in plants increases it causes a decrease in the concentration of elements such as nitrogen, phosphorus, zinc, iodine. When the essential nutrients in crop decrease it cause micronutrient malnutrition in society, commonly known as hidden hunger. In this condition, the body is not nutritionally satisfied and therefore continues to be hungry. And the price of food rise and there is the shift towards less expensive food which is high in calories and fats, animal products. This increases obesity and diet-related diseases. With the degradation of protective coral reefs through acidic erosion, bleaching, and death, saltwater can infiltrate fresh groundwater supplies that large populations depend on. Warming ocean waters generate larger and more devastating weather events that can decimate coastal populations especially without the protection of coral reefs.

The health of our oceans has a direct effect on healthy humans. According to Small and Nicholls, they estimated that 1.2 billion people worldwide, lived in the near-coastal region (within 100 km and 100m of the shoreline). This data was collected in 1990 and therefore is a conservative estimate in modern terms. In the U.S. alone 53% of the population lives within 50 miles of the coastal shoreline. Humans rely heavily on oceans for food, employment, recreation, weather patterns, and transportation. In the U.S. alone the lands adjacent to the oceans contribute over $1 trillion annually through these various activities not to mention pharmaceutical and medicinal discoveries. In all, the oceans are very important for our survival as a species.

In 2016 the United Nations Environment Programme published a report called: "UNEP FRONTIERS 2016 REPORT". In this report, the second chapter was dedicated to Zoonotic diseases, e.g., diseases that pass from animals to humans Deforestation, Climate change, and livestock agriculture are among the main causes that increase the risk of such diseases. It was mentioned that every 4 months a new disease is discovered in humans. It was said that outbreaks that already happened (as of 2016) led to a loss of lives and financial losses of billions of dollars and if future diseases will turn into pandemics it will cost trillions of dollars. The human body requires evaporative cooling to prevent overheating, even with a low activity level. With excessive ambient heat and humidity, adequate evaporative cooling does not take place. Human thermoregulatory capacity is exceeded. A sustained wet-bulb temperature or Wet-bulb globe temperature exceeding about 35 °C (95 °F) can be fatal. Human response to heat stress can be hyperthermia, heatstroke, and other harmful effects. Heat illness can relate to many of the organs and systems including the brain, heart, kidneys, liver, etc.

About the Author: Naila Ishaq is a student of Environmental Science at GCWUS.

Edited By: Amina Shahzadi