Is the weather actually becoming more extreme? - R. Saravanan
-
0:06 - 0:09From 2016 to 2019,
-
0:09 - 0:13meteorologists saw record-breaking
heat waves around the globe, -
0:13 - 0:17rampant wildfires
in California and Australia, -
0:17 - 0:22and the longest run
of category 5 tropical cyclones on record. -
0:22 - 0:27The number of extreme weather events
has been increasing for the last 40 years, -
0:27 - 0:31and current predictions suggest
that trend will continue. -
0:31 - 0:34But are these natural disasters
simply bad weather? -
0:34 - 0:37Or are they due to our changing climate?
-
0:37 - 0:39To answer this question
-
0:39 - 0:43we need to understand the differences
between weather and climate— -
0:43 - 0:48what they are, how we predict them,
and what those predictions can tell us. -
0:48 - 0:52Meteorologists define weather
as the conditions of the atmosphere -
0:52 - 0:55at a particular time and place.
-
0:55 - 0:58Currently, researchers can predict
a region’s weather for the next week -
0:58 - 1:01with roughly 80% accuracy.
-
1:01 - 1:05Climate describes a region’s
average atmospheric conditions -
1:05 - 1:09over periods of a month or more.
-
1:09 - 1:13Climate predictions can forecast
average temperatures for decades to come, -
1:13 - 1:18but they can’t tell us what specific
weather events to expect. -
1:18 - 1:22These two types of predictions
give us such different information -
1:22 - 1:25because they’re based on different data.
-
1:25 - 1:26To forecast weather,
-
1:26 - 1:30meteorologists need to measure
the atmosphere’s initial conditions. -
1:30 - 1:35These are the current levels
of precipitation, air pressure, humidity, -
1:35 - 1:40wind speed and wind direction
that determine a region’s weather. -
1:40 - 1:45Twice every day, meteorologists
from over 800 stations around the globe -
1:45 - 1:48release balloons into the atmosphere.
-
1:48 - 1:52These balloons carry instruments
called radiosondes, -
1:52 - 1:53which measure initial conditions
-
1:53 - 1:57and transmit their findings
to international weather centers. -
1:57 - 2:01Meteorologists then run the data
through predictive physics models -
2:01 - 2:04that generate the final weather forecast.
-
2:04 - 2:07Unfortunately, there’s something stopping
this global web of data -
2:07 - 2:10from producing a perfect prediction:
-
2:10 - 2:13weather is a fundamentally
chaotic system. -
2:13 - 2:18This means it’s incredibly sensitive
and impossible to perfectly forecast -
2:18 - 2:22without absolute knowledge
of all the system’s elements. -
2:22 - 2:24In a period of just ten days,
-
2:24 - 2:30even incredibly small disturbances can
massively impact atmospheric conditions— -
2:30 - 2:35making it impossible to reliably
predict weather beyond two weeks. -
2:35 - 2:39Climate prediction, on the other hand,
is far less turbulent. -
2:39 - 2:42This is partly because a region’s climate
is, by definition, -
2:42 - 2:45the average of all its weather data.
-
2:45 - 2:48But also because climate forecasts ignore
-
2:48 - 2:51what’s currently happening
in the atmosphere, -
2:51 - 2:54and focus on the range
of what could happen. -
2:54 - 2:58These parameters are known
as boundary conditions, -
2:58 - 3:03and as their name suggests, they act
as constraints on climate and weather. -
3:03 - 3:07One example of a boundary condition
is solar radiation. -
3:07 - 3:12By analyzing the precise distance
and angle between a location and the sun, -
3:12 - 3:16we can determine the amount of heat
that area will receive. -
3:16 - 3:19And since we know how the sun
behaves throughout the year, -
3:19 - 3:23we can accurately predict
its effects on temperature. -
3:23 - 3:25Averaged across years of data,
-
3:25 - 3:30this reveals periodic patterns,
including seasons. -
3:30 - 3:35Most boundary conditions have well-defined
values that change slowly, if at all. -
3:35 - 3:39This allows researchers to reliably
predict climate years into the future. -
3:39 - 3:42But here’s where it gets tricky.
-
3:42 - 3:44Even the slightest change
in these boundary conditions -
3:44 - 3:49represents a much larger shift
for the chaotic weather system. -
3:49 - 3:53For example, Earth’s surface temperature
has warmed by almost 1 degree Celsius -
3:53 - 3:56over the last 150 years.
-
3:56 - 3:59This might seem like a minor shift,
-
3:59 - 4:02but this 1-degree change
has added the energy equivalent -
4:02 - 4:07of roughly one million
nuclear warheads into the atmosphere. -
4:07 - 4:12This massive surge of energy
has already led to a dramatic increase -
4:12 - 4:16in the number of heatwaves,
droughts, and storm surges. -
4:16 - 4:22So, is the increase in extreme weather
due to random chance, or changing climate? -
4:22 - 4:23The answer is that—
-
4:23 - 4:26while weather will always
be a chaotic system— -
4:26 - 4:32shifts in our climate do increase
the likelihood of extreme weather events. -
4:32 - 4:37Scientists are in near universal agreement
that our climate is changing -
4:37 - 4:40and that human activity
is accelerating those changes. -
4:40 - 4:42But fortunately,
-
4:42 - 4:46we can identify what human behaviors
are impacting the climate most -
4:46 - 4:50by tracking which boundary conditions
are shifting. -
4:50 - 4:54So even though next month’s weather
might always be a mystery, -
4:54 - 4:59we can work together to protect
the climate for centuries to come.
- Title:
- Is the weather actually becoming more extreme? - R. Saravanan
- Speaker:
- R. Saravanan
- Description:
-
View full lesson: https://ed.ted.com/lessons/is-the-weather-becoming-more-extreme-r-saravanan
From 2016 to 2019, the world saw record-breaking heat waves, rampant wildfires, and the longest run of category 5 tropical cyclones on record. The number of extreme weather events has been increasing for the last 40 years, and current predictions suggest that trend will continue. So, is the increase in extreme weather due to random chance, or changing climate? R. Saravanan investigates.
Lesson by R. Saravanan, directed by Hype CG.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 05:02
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