Climate
Change

The world is increasingly facing worse weather patterns due to climate change, scientists warn. Long-term data have shown how glaciers are shrinking and receding.

The average global sea surface temperature — the temperature of the upper few metres of the ocean — has increased by approximately 0.13°C per decade over the past 100 years, according to latest National Oceanic and Atmospheric Administration data.

Together, glacier recession and thermal expansion of the ocean account for 75% of today's observed sea level rise.

The greenhouse effect

The Sun is the main source of energy on Earth. Our planet absorbs some of the Sun’s energy, and radiates the rest back towards space. However, certain gases in the atmosphere — called 'greenhouse gases' — absorb some of the energy radiated from the Earth. They trap these gases in the atmosphere. In general, it works as follows:

(1) Energy from the Sun arrives to the Earth as solar radiation.

2) Some solar radiation is reflected by the Earth and the atmosphere. Most radiation is absorbed by the Earth's surface and warms it.

(3) Infrared (heat) radiation is emitted by the Earth's surface. While some “escape” the atmosphere, some are absorbed and re-emitted in all directions by greenhouse gas molecules. The effect: keeping the Earth's surface and the lower atmosphere warm. It’s a delicate balance.

Energy: The biggest climate driver

Source: Climate Science Investigations

The balance between incoming energy from the Sun and outgoing energy from the Earth ultimately drives our climate.

There are processes that balance the incoming solar radiation and the outgoing terrestrial radiation.

To balance the absorbed incoming energy, the Earth must, on an average, emit the same amount of radiation back to space.

Weather vs Climate

The weather changes daily, even hourly sometimes. The changes we see and feel outside — rainy one day and sunny the next — that’s the weather. It can be cold, or hot too. Weather also changes from place to place.

Climate, on the other hand, is the 'usual weather' of a place. Different places can have different climates, and it changes with seasons. A place might be mostly warm and dry in the summer. The same place may be cool and wet in the winter.

Then there's the Earth's climate, too — the combination of all the climates around the world together.

Climate has changed throughout Earth's long history. So while weather can change in just a few hours, or from one day to another, climate takes hundreds — or even millions — of years to change.

The Intergovernmental Panel on Climate Change (IPCC) defines climate change as “a change in the state of the climate that can be identified (using statistical tests) by changes in the mean and/or the variability of its properties. This change persists for an extended period.”

Scientists see changing patterns of the usual weather. Human activity — specifically, by burning more greenhouse gases and spewing them into the Earth's atmosphere — turns up the heat on the planet.

Carbondioxide

Credit: NASA / Source: Atmospheric Infrared Sounder (AIRS).

A series shows global changes in the concentration and distribution of CO2 since 2002 at an altitude range of about 3 to 13 kms. The yellow-to-red regions show higher concentrations of CO2, while blue-to-green areas indicate lower concentrations, measured in parts per million (ppm).

Global temperature

Credit: GISS / Source: NASA Scientific Visualization Studio

A colour-coded map shows the progression of changing global surface temperatures since the 1880s. Dark blue indicates areas cooler than average. Dark red indicates areas warmer than average.

Receding sea ice

Source: Satellite Observations / NASA Scientific Visualisation Stiudio

This is the annual Arctic sea ice minimum, from 1980 to 2020. At the end of each summer, the sea ice cover reaches its minimum extent, leaving what is called the 'perennial ice cover'. It has been receding since satellite record began in 1979.

People who deny climate change

There are people, among them scientists, who deny climate change, even calling it a “hoax”. They say the long term changes to global climate form part of the natural world.

The concept of global warming was created for the Chinese in order to make US manufacturing non-competitive.

Donald Trump, former president of the United States

“Fear of the coming ice age is old hat, but fear that manmade greenhouse gases are causing temperatures to rise to harmful levels is in vogue now. That is popular. Go in any establishment in Washington and the liberals are talking about global warming … Man-made global warming is the greatest hoax ever perpetrated on the American people.”

US Senator James Inhofe, Author of the book 'The Greatest Hoax: How the Global Warming Conspiracy Threatens Your Future'

”Some small fraction of the 1 °C warming during the past two centuries must have been due to increasing CO2, which is indeed a greenhouse gas… (but) most of the warming has probably been due to natural causes."

Dr William Happer, US physicist (atomic physics, optics and spectroscopy expert)

“Scientists who dissent from the alarmism have seen their grant funds disappear, their work derided, and themselves libelled as industry stooges, scientific hacks or worse. Consequently, lies about climate change gain credence even when they fly in the face of the science that supposedly is their basis.”

Richard Siegmund Lindzen, US atmospheric physicist, emeritus professor of meteorology, MIT

The Earth is warming but physical evidence from around the world tells us that human-emitted carbon dioxide has played only a minor role in it. Instead, the mild warming seems to be part of a natural 1,500-year climate cycle (plus or minus 500 years) that goes back at least one million years.

Fred Singer, atmospheric physicist and professor emeritus of environmental science at the University of Virginia

America’s strength lies not in its one-ness, but in its diversity of beliefs and efforts. And it will take all our strength in the coming years to combat global warming alarmism and to keep America from falling into the totalitarian green abyss.

Steven Milloy, Fox News columnist, publisher of JunkScience.com

Climate change is not by human behaviour but by various exogenous and endogenous natural processes (such as fluctuating solar activity). Climate change is a new wave of dangerous indoctrination of the whole world…global-warming alarmism is challenging our freedom.

Vaclav Klaus, ex-president, Czech Republic

Where we stand today


Credit: Unsplash

Carbon neutrality

Carbon neutrality means having a balance between emitting carbon and absorbing carbon from the atmosphere in carbon sinks, a system that absorbs more carbon than it emits.

Bhutan and Suriname

They are the only countries that have achieved carbon neutrality so far.

Some key countries that have carbon-neutral target in place by law:

Finland (2035)

Sweden (2045)

UK (2050)

France (2050)

Denmark (2050)

New Zealand (2050)

Hungary (2050)

Japan (2050)

China (2060)

Top achievers

Finland

Zero per cent of its population is exposed to air pollution. Finland is aiming to achieve carbon neutrality by 2035.

Norway

Only 2% of the people are exposed to air pollution. Its carbon neutrality target is 2050.

New Zealand

Zero per cent of the population is exposed to air pollution. One-third of its area is protected by the government. The country has met its target for reducing greenhouse emissions under Kyoto Protocol and has set additional goals for 2030 and 2050.

Australia

The country has the second-highest percentage of protected land and marine areas. Lauded for its plastic ban, reduction of food waste and alternative energy pursuits.

USA

The US has promised to cut its emissions by at least 50% by 2030, more than double its pledge under Paris Agreement. More than 25% of the US territory is protected area.

Peru

On April 1, 2018, Peru became the first in the world to set up a specialised environmental court or juzgado ambiental. The court deals with illegal mining, deforestation, illicit wildlife trade and handling hazardous waste.

Tunisia

Set up Green Police in 2017 to tackle illegal dumping.

Global Warming

Can we just ignore it? Leave it today, for our children to deal with it later?

Global warming is the heating of the Earth in the long term due to human activities. Since the pre-industrial period, Earth’s average temperature has increased by about 1 degree Celsius. Data collected over the years provides unequivocal evidence of global warming.

Melting glaciers, rising sea levels, dying forests, and vanishing wildlife are some clear signs. This summer, some 10 million acres of land are burning in Siberia, where the annual average temperature is about 0.5 °C (32.9 °F).

What is the Earth's atmosphere made of?

Our atmosphere is made up of a unique mix of molecules of the following:

. Infrared radiation

. Nitrogen

. Oxygen

They're 'unseen' by the naked eye, as though they are 'transparent'. These three gases form part of the Earth's delicate balance. However, they're not transparent at all to the radiation the Earth produces, including:

. Water (H20)

. Carbon dioxide (CO2), and

. Methane (CH4)


Source: Weather and Climate

Sources of greenhouse gases

The biggest source of greenhouse gas emissions from human activities is from burning fossil fuels for electricity, heat, and transportation. In the US, most of the emissions of human-caused (anthropogenic) greenhouse gases (GHG) come primarily from burning fossil fuels — coal, natural gas, and petroleum — for energy use.

The Paris Agreement

The agreement brought together close to 200 countries for the first time in undertaking efforts to combat global change.

It’s a legally-binding international treaty on climate change adopted on December 12, 2015 and entered into force on November 4, 2016.

The agreement aims to limit global warming to less than 2 degrees Celsius, preferably to 1.5°C, compared to pre-industrial levels, within the current century.

It set targets for developed nations to cut emissions; they should take the lead in providing financial assistance to countries that are less capable and more vulnerable.

197 countries have endorsed the Paris Agreement

190 countries have approved it formally

Three major countries that didn’t join: Turkey, Iran, Iraq



Going around in cycles

Our lives literally revolve around cycles. The cycles play key roles in Earth’s short-term weather and long-term climate.

Source: California Academy of Sciences

Earth’s spin

Earth's eastward rotation (or 'Earth's spin') is the rotation of planet around its own axis. So, it takes 24 hours to do. It also refers to the changes in the orientation of the rotation axis in space. The Earth moves around the Sun in an elliptical orbit, making a complete revolution in a year (365.24 days/1 year).

Changes in obliquity

The Earth’s axial change, or tilt, does affect the climate, specifically the temperature and the amount of ice and water on the planet. Our planet’s axis is calculated to oscillate between 22.1° and 24.5° on a 41,000-year cycle.

In terms of rotational axis — the Earth's axial tilt (obliquity) is currently about 23.4° (in relation to the plane of Solar System).

The Moon plays a big part in stabilising this tilt.

Axial precession

In astronomy, axial precession is a gravity-induced, slow, and continuous change in the orientation of an astronomical body's rotational axis.

In particular, it can refer to the gradual shift in the orientation of Earth's axis of rotation in a cycle of approximately 26,000 years.

Axial precession plays a role in seasonal contrasts: more extreme in one hemisphere and less extreme in the other.

Currently perihelion (point in the Earth’s orbit closest to the sun) occurs during winter in the Northern Hemisphere and in summer in the Southern Hemisphere. This makes Southern Hemisphere summers hotter and moderates Northern Hemisphere seasonal variations.

Changes in eccentricity

Eccentricity measures how much the shape of Earth's orbit departs from a perfect circle. These variations affect the Earth-Sun distance.

Currently, a difference of only 3% (5 million km) exists between closest approach (perihelion”, occurs around January 3), and furthest departure (“aphelion”, occurs around July 4).

Eccentricity almost exclusively controls the total amount of solar radiation received by Earth in a year.

These small variations in how Earth moves around our Sun, influence our climate over very long timespans. Scientists say, however, that these can't account for Earth's current period of rapid warming.


Source: Nasa

People who say it is bad

The International Panel on Climate Change report warns of damage caused by human activity and forecasts worse weather.

International Panel on Climate Change report

Carbon dioxide in the atmosphere has reached the highest level in 2 million years, leading to warmer temperatures. Since 1970, temperatures have soared faster than in any other 50-year period in the last 2,000 years. The trends of intense heatwaves, heavy rainfall causing floods and drier droughts are linked to the human influence on the climate.

Linda Mearns, a senior climate scientist at the US National Centre for Atmospheric

Extreme weather is already a factor in many places. Heatwaves and drought are driving wildfires in the western United States, while extreme heat is fuelling fires in Greece and Turkey. It’s just guaranteed that it’s going to get worse. Nowhere to run, nowhere to hide.

Panmao Zhai, Chinese climatologist, Secretary-General of the Chinese Meteorological Society

Stabilising the climate will require strong, rapid, and sustained reductions in greenhouse gas emissions and reaching net-zero CO2 emissions. Limiting other greenhouse gases and air pollutants, especially methane, could have benefits both for health and the climate.

"We don't just need goals for just 2030 or 2050. We, above all, need them for 2020 and every following month and year to come. ‘Net zero emissions by 2050’ for the EU equals surrender. It means giving up.”

Greta Thunberg, climate activist

“Even the solutions that we have considered big and bold are nowhere near the scale of the actual problem that climate change presents to us.”

US Rep Alexandria Ocasio-Cortez (New York)

“Renewable energy is no longer a niche fuel. We should not cling to crude down to the last drop - we should leave oil before it leaves us."

Fatih Birol, Executive Director, International Energy Agency

5 facts to know

There are at least five lines of scientific evidence showing the Earth's climate is changing:

Image Credit: AP

1: Paleoclimate

Earth's climate has changed throughout history. Just in the last 650,000 years there have been seven cycles of glacial advance and retreat.

The last ice age, about 11,700 years ago, had an abrupt end. This marked the start of the modern climate era — and of human civilisation. Most of these climate changes are attributed to very small variations in Earth’s orbit that change the amount of solar energy our planet receives.

How do scientists know this?

Evidence of the Earth’s climate responding to greenhouse gas levels can be found, for example, in ice cores drawn from Greenland, Antarctica, and tropical mountain glaciers. This climate information from the ancient period, known as paleoclimate, reveals that current warming is occurring roughly 10 times faster than the average rate of ice-age-recovery warming.

Carbon dioxide from human activity is increasing more than 250 times faster than it did from natural sources after the last Ice Age, according to top climate scientists.

The current warming trend is remarkable as most of it is extremely likely (greater than 95% probability) to be the result of human activity since the mid-20th century and proceeding at a rate that is unprecedented over thousands of years.

Image Credit: AFP

2: Atmospheric CO2

The heat-trapping properties of carbon dioxide (CO2) — and other gases like methane — in the atmosphere was demonstrated in the late 1930s.

In 1938, British scientist Guy Callendar linked CO2 increases in Earth’s atmosphere to global warming.

In 1941, Serbian mathematician and geophysicist Milton Milankovic linked Ice Ages to the Earth’s orbital characteristics.

In 1956, Canadian physicist Gilbert Plass formulated the Carbon Dioxide Theory of Climate Change. For many years, Earth-orbiting satellites and other technological advances have enabled scientists to see the big picture, collecting numerous types of information about our planet and its climate on a global scale. This body of data, collected over many years, reveals the signals of a changing climate.

Nasa has flown many environmental satellites, starting with the first weather exploration satellite Explorer VII, flown in 1959.

Nasa alone has 16 Earth-observing satellites operating in orbit around our planet. Its instruments are highly accurate in measuring the presence of CO2 in the atmosphere. CO2’s ability to affect the transfer of infrared energy through the atmosphere is the scientific basis of many instruments flown by Nasa. There is no question that increased levels of greenhouse gases causes the Earth to warm as a result.

A kangaroo rushes past a burning house in Lake Conjola, Australia. The fire season in 2020 was one of the worst in Australia's history, with lives lost, hundreds of homes destroyed and millions of acres burned.
Image Credit: NYT

Evidence 3: Rising surface temperature

The planet's average surface temperature has risen about 2.12 degrees Fahrenheit (1.18 degrees Celsius) since the late 19th century. This change has been driven largely by increased CO2 emissions into the atmosphere and other human activities, according to the US National Oceanic and Atmospheric Administration (NOAA). Most of the surface temperature warming occurred in the past 40 years, with the seven most recent years being the warmest. The years 2016 and 2020 are tied for the warmest year on record.

Image Credit: AFP

Evidence 4: Warming Ocean

The ocean has absorbed much of this increased heat, with the top 100 metres (about 328 feet) of ocean showing warming of more than 0.6 degrees Fahrenheit (0.33 degrees Celsius) since 1969, according to a NOAA data set. Earth stores 90% of the extra energy in the ocean.

Image Credit: AP

Evidence 5: Shrinking Ice Sheets

The earth's ice caps are shrinking, and fast. Scientists say the main reason is a warming ocean under the ice. A new survey of satellite data shows that Greenland and Antarctic ice sheets have significantly decreased in mass over the past few decades. Data from NASA's Gravity Recovery and Climate Experiment show Greenland lost an average of 279 billion tonnes of ice per year between 1993 and 2019; Antarctica lost about 148 billion tonnes of ice per year, according to a 2020 research published in the scientific journal Geophysical Research Letters.

8 Ways you can help

1. Save energy: Use air-conditioners judiciously and unplug electronic devices when they are not in use.

2. Wash clothes in cold water and hang-dry your clothes instead of using a drier.

3. Use energy-efficient light bulbs.

4. Climate-friendly diet: Eat more vegetarian meals.Buy more organic and localproduce. Grow your vegetables. Avoid wasting food.

5. Green commute: Take public transport, try car-pooling, buy an electric or hybrid car.

6. Avoid plastic: Stop using plastic carry-bags and instead use jute or cloth bags. Switch to steel straws, glass tumblers and bottles, and steel cutlery.

7. Reduce wastage: Never buy more than required. Bulk buying leads to wastage.

8. Work smart: High productivity is possible in many remote-work situations.

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